Abstract: The invention relates to a thrombolytic enzyme referred to as Thrombinase having a molecular weight of 31,000 to 32,000. Such a thrombolytic enzyme can be used for dissolving blood clots. The process comprises culturing a filtrate of Bacillus sphaericus sero type H5a 5b, removing the cell, subjecting the cell supernatant to filtration, salting out the retentate, subjecting the precipitate to dialysis, reprecipitating the precipitate and then reconstituting in buffer and finally decolorizing, purifying and dialyzing.

Abstract: Disclosed is a composition for preventing and treating acetaminophen induced liver injury including the protein extracted from Porphyra yezoensis. The protein(s), separated and purified from hot water extracts of Porphyra yezoensis, having the molecular weight of 14 kDa measured by sodium dodecyl sulfate polyacrylamide gel electrophoresis, has an excellent effect for inhibiting the oxidative injury of liver tissue and cell apoptosis of liver cells induced by acetaminophen.

Abstract: A magnetic particle and fabrication method thereof. The magnetic particle comprises a polymer core, a magnetic material layer covering the polymer core, and a silicon containing layer covering the magnetic material layer. In addition, the magnetic particle may further comprise a coupling agent on the silicon containing layer, and an active molecule connected to the coupling agent. The magnetic particles provide controllable size, uniform diameter distribution, high magnetization, improved storage stability, and modified surface for targeting biomolecules for biomaterial separation and environmental analysis.

Abstract: Magnetic particles are prepared containing a magnetic core coated with a glass layer having a substantially pore-free glass surface or having pores with a diameter of less than 10 nm. The particles are used for separating biological material such as nucleic acids. A preferred process of preparing the particles is by forming a mixture of magnetic cores with a sol formed from an alcohol and a metal alkoxide, spray-drying the mixture to coat the cores with a layer of gelled sol, and heating the coated cores to obtain the magnetic glass particles. Preferably, the particles have an average particle size of less than 100 ?m. The magnetic core may be a composite material containing a mica core and magnetite particles immobilized on the mica core, and the glass layer may contain boron oxide. Magnetic core materials include magnetite (Fe3O4) and Fe2O3.

Abstract: Disclosed is a method for performing the steps of nucleic acid template purification, thermocycling reaction and purification of the products of the thermocycling reaction characterized in that the steps take place sequentially in a microfluidic disc. Also disclosed is a microstructure for fluids comprising at least one inlet opening connected to a first chamber incorporating a means for purifying template nucleic acid which, in turn, is connected to a second chamber incorporating a means for a thermocycling reaction which, in turn, is connected to a third chamber incorporating a means for purifying products of the thermocycling reaction, and a microfluidic disc comprising a plurality of such microstructures.

Abstract: Reagents, methods and kits for denaturation of protein are provided.

Abstract: This invention provides methods of retentate chromatography for resolving analytes in a sample. The methods involve adsorbing the analytes to a substrate under a plurality of different selectivity conditions, and detecting the analytes retained on the substrate by desorption spectrometry. The methods are useful in biology and medicine, including clinical diagnostics and drug discovery.

Abstract: This invention provides methods of retentate chromatography for resolving analytes in a sample. The methods involve adsorbing the analytes to a substrate under a plurality of different selectivity conditions, and detecting the analytes retained on the substrate by desorption spectrometry. The methods are useful in biology and medicine, including clinical diagnostics and drug discovery.

Abstract: The invention provides methods and compositions for azide tagging of biomolecules. In one embodiment of the invention, proteins are tagged by metabolic incorporation of prenylated azido-analog substrates. Examples of such analogs are azido farnesyl diphosphate and azido farnesyl alcohol. The azido moiety in the resulting modified proteins provides an affinity tag, which can be chemoselectively captured by an azide-specific conjugation reaction, such as the Staudinger reaction, using a phosphine capture reagent. When the capture agent is biotinylated, the resulting conjugates can be detected and affinity-purified by streptavidin-linked- HRP and streptavidin-conjugated agarose beads, respectively. The invention allows detection and isolation of proteins with high yield, high specificity, and low contamination without harsh treatment of proteins.

Abstract: A process for preparing beta-fructofuranosidase enzyme and a process for producing fructooligosaccharides, in which the preparation of the enzyme is obtained by cultivating the fungus Aspergillus niger, either wild or mutated, in a preferably semi-solid culture medium, in order to produce an extracellular enzyme, which is submitted to transfructosylation for producing fructooligosaccharides comprising sugars which are formed by one unit of sacrose and by two, three and four units of fructose.

Abstract: A process for purifying a phosphodiesterase 1 (PDE-1) from a cell including heating an extract of a cell formed from a solution including at least one divalent cation, to increase the specific activity of PDE-1 in the extract.

Abstract: Disclosed is a method for performing the steps of nucleic acid template purification, a thermocycling reaction and purification of the products of the thermocycling reaction characterised in that the steps take place sequentially in a microfluidic disc. Also disclosed is a microstructure for fluids comprising at least one inlet opening connected to a first chamber incorporating a means for purifying template nucleic acid which, in turn, is connected to a second chamber incorporating a means for a thermocycling reaction which, in turn, is connected to a third chamber incorporating a means for purifying products of the thermocycling reaction, and a microfluidic disc comprising a plurality of such microstructures.

Abstract: A method for simply and conveniently detecting acetyltransferase and deacetylase activities of proteins by executing an acetylation reaction of a peptide substrate with an acetyltransferase, or a deacetylation reaction of an acetylated peptide substrate with a deacetylase, and after the completion of these reactions, detecting the acetyl group bound to the peptide substrate by using an anti-acetylated peptide antibody. This system for detecting acetyltransferase and deacetylase activities using the anti-acetylated peptide antibody enables screening inhibitors or enhancers of acetyltransferase and deacetylase. A system for screening deacetylase inhibitors or acetyltransferase enhancers using cultured cells is also provided.

Abstract: Magnetic particles are prepared containing a magnetic core coated with a glass layer having a substantially pore-free class surface or having pores with a diameter offices than 10 nm. The particles are used for separating biological material such as nucleic acids. A preferred process of preparing the particles is by forming a mixture of magnetic cores with a sol formed from an alcohol and a metal alkoxide, spray-drying the mixture to coat the cores with a layer of gelled sol, and heating the coated cores to obtain the magnetic glass particles. Preferably, the particles have an average particle size of less than 100 ?m. The magnetic core may be a composite material containing a mica core and magnetite particles immobilized on the mica core, and the glass layer may contain boron oxide. Magnetic core materials include magnetite (Fe3O4) and Fe2O3.

Abstract: The present invention concerns a method for enzymatic treatment of lignocellulosic materials which contain xylan-polymers, such as cellulose kraft pulps. According to a method of the present kind, at least a part of the hexenuronic acid groups present in the material is selectively removed in order to remove metal ions from the pulp, to change the surface charge thereof, to improve the brightness stability of the pulp and to render the material more suitable for enzymatic treatment.

Abstract: The present invention provides methods of purification of Hepatitis A Virus from the supernatant of an infected cell culture and production of a preparation of purified HAV antigen. The present invention is also directed to an HAV vaccine composition comprising a preparation consisting of purified mature HAV particles in an amount sufficient to induce a protective immune response in a mammal.

Abstract: Provided are affinity support materials having intermediate binding affinity for biological samples. Among the materials provided by the present invention are hydrophilic solid supports composed of hydrophilic ligands coupled to hydrophilic matrixes which are compatible with biological samples, for example, a cell line, a biological fluid such as blood, or a tissue cell lysate. The ligands may include affinity property groups and hydrophilic groups pendent from a backbone, and be configured to at least partially resolve components of a biological sample. Affinity supports in accordance with the present invention may be used in a variety of techniques and apparatuses to achieve improved separations of complex biological samples and thereby enhance the results of biological sample component fractionations, enrichments, purifications, expression product determinations and comparisons, and other biological sample processing techniques.

Abstract: The present disclosure relates to a method for determining cholesterol in low density lipoprotein comprising the steps of (a) measuring total cholesterol level in a sample containing at least high density lipoprotein, low density lipoprotein, very low density lipoprotein and chylomicron, and (b) measuring cholesterol levels in the high density lipoprotein, very low density lipoprotein and chylomicron in the sample, wherein the cholesterol level in the low density lipoprotein is determined by subtracting a value obtained in the step (b) from a value obtained in the step (a). The present invention enables concurrent determination of cholesterol level in low density lipoprotein and total cholesterol level, facilitating acquisition of two types of biological information at a time.

Abstract: The present invention concerns a method for enzymatic treatment of lignocellulosic materials which contain xylan-polymers, such as cellulose kraft pulps. According to a method of the present kind, at least a part of the hexenuronic acid groups present in the material is selectively removed in order to remove metal ions from the pulp, to change the surface charge thereof, to improve the brightness stability of the pulp and to render the material more suitable for enzymatic treatment.

Abstract: The present invention relates to a method for the quantitative release of natural or recombinant proteins, polypeptides (thermostable immunoligands) able to bind to the Fc-part of immunoglobulins (antibodies, in particular of the IgG class and primarily becoming bound outside the paratope) from complexes in various sample matrixes in order to make these released natural or recombinant proteins, polypeptides or peptides quantitatively available in immunochemical assays and to keep them quantitatively available. The method is characterized by mixing the sample with reagent compound that is able to bind non-specifically to immunoglobulins, and thereafter subjecting the sample to a heat treatment step followed by a cooling step.

Abstract: The present invention involves a method for assaying a substance. The method of the present invention comprises contacting the substance with an assay agent comprising a catalytic agent to associate the substance with the catalytic agent, contacting the resulting associated substance with a label precursor capable of reacting catalytically with the catalytic agent to release the label, and detecting a mass label. The present invention also involves a kit for assaying a substance. The kit of the present invention comprises an assay agent comprising a catalytic agent, and a label precursor capable of reacting catalytically with the catalytic agent to release a mass label.

Abstract: The invention concerns a method for the purification of a target substance from a biological sample by immobilizing the target substance on a solid phase by means of a high affinity binding pair and subsequently eluting it by adding a partner of the binding pair in a free form. In addition reagent kits for carrying out the method are disclosed.

Abstract: The present invention provides a crystallization process wherein a starting temperature is selected such that a desirable crystal morphology (e.g., square) is obtained. A temperature shift is then introduced, providing that the shift is not enough to induce further nucleation, where the crystals continue to grow in the desirable fashion, but with different kinetics, e.g., a higher rate of crystallization. As a result, the process gives a crystalline product with desirable morphology at a higher crystallization rate.

Abstract: The invention relates to an immunogenic composition, characterized in that it comprises an adenyl cyclase-hemolysin (AC-Hly) protein, or an immunogenic portion of this AC-Hly, of a strain of Bordetella chosen from B. pertussis, B. parapertussis or B bronchiseptica, and in that it comprises, in addition, a bacterial extract containing the expression products of the vrg genes of a strain of Bordetella chosen from B. pertussis, B. parapertussis or B bronchiseptica, or a portion of these expression products which is sufficient to induce an immune response in a host to which the extract might be administered.

Abstract: The present invention relates to a filtration-detection device for detecting or quantifying an analyte in a test sample including a filtration device having a first binding material immobilized thereto, wherein the first binding material is capable of binding to a portion of the analyte, and a detection assembly positioned relative to the filtration device to detect or quantify analyte bound to the first binding material. The present invention also relates to methods of using the filtration-detection device.

Abstract: Processes for preparing oligosaccharides, polysaccharides, glycolipids, glycoproteins, and other saccharide compositions are provided which involve the enzyme facilitated transfer of a preselected saccharide unit from a donor moiety to an acceptor moiety. In accordance with a preferred embodiment, saccharide compositions having a plurality of saccharide units are prepared by appending the saccharide units in iterative fashion to acceptor moieties which are themselves saccharide compositions prepared in accordance with this invention.

Abstract: The utility of soybeans having a composition of greater than 40% of the protein as beta-conglycinin and less than 10% of the protein as glycinin for making highly functional high beta-conglycinin compositions was discovered. The discovered ingredients are useful for mimicking the texturizing properties of casein while also maintaining or improving physiological benefits of soy protein ingredients (e.g., cholesterol and triglyceride lowering properties). The high stability of the high beta-conglycinin compositions against protein—protein aggregation reactions is valuable for creating good tasting beverages and beverage mixes. Cheese with good spreadability, gloss and smoothness was made using an enzyme-modified version of the new ingredient composition. Cheese with good firmness and meltability was also created using a different enzyme-treatment. High beta-conglycinin compositions were found to demonstrate excellent emulsifying and gelling properties in the pH region (5.5-6.

Abstract: A method is provided for the extraction of water soluble biomaterials such as enzymes or proteins into carbon dioxide utilizing certain carbon dioxide soluble surfactants. The extraction can be performed on an aqueous solution, a fermentation broth or a fluid. The method includes the process steps of forming a carbon dioxide/surfactant mixture which involves dissolving carbon dioxide soluble surfactant(s) in carbon dioxide. The carbon dioxide can be in a liquid or supercritical form and the surfactant includes tail and head groups that interact with the biomaterials. Further, the mixture is added to the aqueous solution, fermentation broth or liquid under conditions to allow for extraction of the biomaterials. The method further includes depressurizing and/or temperature adjusting to remove the water soluble biomaterials. The surfactants include fluroethers, oligomers of propylene-oxide, siloxanes, etc. The biomaterials include proteins or enzymes. The carbon dioxide is suberitical or supercritical.

Abstract: This invention relates methods for conditioning affinity chromatography resins to decrease leaching of the ligand during purification. The methods involve incubating the resin in a buffered solution of a hydroxyalkylamine compound (e.g., ethanolamine) prior to use of the resin for an affinity purification. The treatment removes unstably bound ligand from the resin.

Abstract: The invention relates to a method for producing optically pure compounds of 3(R)- and 3(S)-hydroxy-1-methyl-4-(2,4,6-trimethoxyphenyl)-1,2,3,6-tetrahydro-pyridine or its carboxylic acid esters by reacting the enantiomer mixtures stereoselectively, using an enzyme.

Abstract: The present invention provides a crystallization process wherein a starting temperature is selected such that a desirable crystal morphology (e.g., square) is obtained. A temperature shift is then introduced, providing that the shift is not enough to induce further nucleation, where the crystals continue to grow in the desirable fashion, but with different kinetics, e.g., a higher rate of crystallization. As a result, the process gives a crystalline product with desirable morphology at a higher crystallization rate. The starting temperature of the process can be between about 4° C. and 20° C. for no more than about 5 hours and the temperature shift of the process can be between about 22° C. and 60° C. for no more than about 20 hours.

Abstract: A kit for testing male fertility comprises a vessel, a base unit, a liquid supply containing liquid and two filters. The first filter is a sample separation filter which forms a hindrance to transmission of spermatozoa. The second filter of the kit is a spermatozoa detection filter comprising a reagent for identifying spermatozoa. Activation of the kit is prevented until a transport medium, such as the liquid, fills a gap allowing spermatozoa to transmit to a detection zone. The kit may be of one-piece construction and utilizes a thin piece of filter material to separate motile from non-motile spermatozoa.

Abstract: The invention relates to an immunogenic composition, characterized in that it comprises an adenyl cyclase-hemolysin (AC-Hly) protein, or an immunogenic portion of this AC-Hly, of a strain of Bordetella chosen from B. Tertussis, B. parapertussis or B. bronchiseptica, and in that it comprises, in addition, a bacterial extract containing the expression products of the vrg genes of a strain of Bordetella chosen from B. pertussis, B. parapertussis or B. bronchiseptica, or a portion of these expression products which is sufficient to induce an immune response in a host to which the extract might be administered.

Abstract: The present disclosure relates to a method for determining cholesterol in low density lipoprotein comprising the steps of (a) measuring total cholesterol level in a sample containing at least high density lipoprotein, low density lipoprotein, very low density lipoprotein and chylomicron, and (b) measuring cholesterol levels in the high density lipoprotein, very low density lipoprotein and chylomicron in the sample, wherein the cholesterol level in the low density lipoprotein is determined by subtracting a value obtained in step (b) from a value obtained in step (a). The present invention enables concurrent determination of cholesterol level in low density lipoprotein and total cholesterol level, facilitating acquisition of two types of biological information at a time.

Abstract: A dry chemistry dye indicator composition provides improved shelf life, stable color indication end point and capability for a system at near normal pH. The novel dry chemistry dye indication system comprises 3-Methyl-6-(sodium sulfonate)-benzothiazolinone-(2)-hydrazone (MBTH-S). A preferred dye systems are based on the dye couple (MBTH-S) and 8-anilino-1-naphthalenesulfonate (ANS), and the dye couple MBTH-S and N-(3-sulfopropyl)analine. These dye indicator systems are used in conventional blood chemistry test strips and are particularly preferred for indication of glucose in blood.

Abstract: The invention relates to a process for the preparation of molecularly imprinted polymers useful for separation of enzymes, which comprises the steps of reacting a complex of enzyme and affinity monomer, a comonomer and a crosslinker, with a polymerization initiator and a polymerization accelerator at ambient temperature and pressure for a period ranging between 2 to 24 hrs, thereby obtaining a crosslinked polymer, crushing the cross linked polymer obtained to fine particles, adding a solvent and extracting imprinted enzyme from the polymer, obtaining the molecularly imprinted polymer, contacting the imprinted polymer with aqueous solution containing imprinted enzyme or a mixture of imprinted enzyme and other enzymes and isolating the enzyme-adsorbed polymer.

Abstract: A method for the purification of human platelet heparanase using chromatographic techniques is described. The method comprises detergent-aided solubilization of a heparanase-containing fraction followed by purification of the heparanase therefrom by concanavalin A, Zn2+-chelating Sepharose, a Blue A or Reactive Red matrix, octyl agarose and gel filtration chromatography. Heparanase so purified has a molecular mass (Mr) of about 50 kDa and degrades both heparin and heparan sulfates.

Abstract: The present invention cloned a cDNA clone encoding isopentenyl diphosphate (hereafter “IPP”) isomerase (EC 5.3.3.2) from a cDNA library of Hevea brasiliensis latex. The clone has a continuous open reading frame encoding a peptide of 234 amino acids with a predicted molecular mass of 26.7 kDa. The deduced protein is acidic with an isoelectric point of 4.7 and shows high sequence identity with other IPP isomerases. The recombinant protein expressed in Escherichia coli showed IPP isomerase activity. In vitro rubber biosynthesis assays using washed rubber particle (WRP) deprived of initiating allylic diphosphates were performed with the addition of IPP isomerase in the reaction mixture. Results revealed that the recombinant IPP isomerase is catalytically active in catalyzing the conversion of IPP to DMAPP, a key activation step of the basic five-carbon isoprene unit in rubber biosynthesis. Southern analysis indicated that the IPP isomerase is encoded by two genes in Hevea rubber tree.

Abstract: Multiphasic microfluidic apparatus for performing product fluid manipulation and separation in a single continuous unit are provided. Related methods, kits, and compositions are also provided.

Abstract: The present invention includes the characterization of the major salivary protein or enzyme of the corn earworm Helicoverpa zea for triggering resistance to bacterial blight and frogeye leafspot in soybeans and for triggering resistance to insects in tomatoes. The invention includes an enzyme or a novel protein secreted from the salivary glands of certain insects including the saliva of species belonging to the order Hymenoptera and Lepidoptera. The regurgitant of Helocoverpa zea obtained from the functional salivary glands contains a protein that possesses glucose oxidase activity. The amino acid sequence of the protein is unique and when the protein is applied to plants, it triggers disease and insect resistance systematically. The physical and kinetic attributes of the enzyme are a pH of 7.0, a pI of 4.4 and a molecular weight of 88 kd. The km and Vmax of the enzyme for glucose is 26.9 mmol and 26.7 &mgr;mol min−1 mg−1, respectively.

Abstract: MPROT12 polypeptides and polynucleotides and methods for producing such polypeptides by recombinant techniques are disclosed. Also disclosed are methods for utilizing MPROT12 polypeptides and polynucleotides in therapy, and diagnostic assays for such.

Abstract: Magnetic glass particles are prepared containing a magnetic core coated with a glass layer having a substantially pore-free glass surface. The particles are used for separating biological material such as nucleic acids. A preferred process of preparing the particles is by forming a mixture of magnetic cores with a sol formed from an alcohol and a metal alkoxide, spray-drying the mixture to coat the cores with a layer of gelled sol, and heating the coated cores to obtain the magnetic glass particles. Preferably, the particles have an average particle size of less than 100 &mgr;m and any pores of the glass surface have a diameter of less than 10 nm. The magnetic core may be a composite material containing a mica core and magnetite particles immobilized on the mica core, and the glass layer may contain boron oxide. Magnetic core materials include magnetite (Fe3O4) and Fe2O3.

Abstract: A method and apparatus for the manipulation of colloidal particles and biomolecules at the interface between an insulating electrode such as silicon oxide and an electrolyte solution. Light-controlled electrokinetic assembly of particles near surfaces relies on the combination of three functional elements: the AC electric field-induced assembly of planar aggregates; the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The present invention provides a set of fundamental operations enabling interactive control over the creation and placement of planar arrays of several types of particles and biomolecules and the manipulation of array shape and size. The present invention enables sample preparation and handling for diagnostic assays and biochemical analysis in an array format, and the functional integration of these operations.

Abstract: A quick assay method for the activity of a plant-derived, asparagine residue-specific endoprotease is disclosed which comprises measuring fluorescence generated by a fluorescence quenching substrate split by an asparagine residue-specific endoprotease. The fluorescence quenching substrate comprises an oligopeptide having in its amino acid sequence at least one asparagine residue, whose C-terminal side is other than an isoleucine residue, a leucine residue, or a valine residue, wherein the oligopeptide has a 7-methoxycoumarin-4-yl-acetyl group arranged on its N-terminal side and a 2,4-dinitrophenyl group arranged on its C-terminal side.

Abstract: A dry chemistry reagent matrix composition is provided containing a matrix material and a reagent composition containing 3-methyl-6(sulfonate salt)-benzothiazolinone-(2)-hydrazone (MBTH-S), N-ethyl-N-(3-sulfopropyl)aniline, and an oxidase enzyme or a peroxidase enzyme or a mixture thereof. The dry chemistry reagent matrix composition is useful in reagent test strips for determining the presence or concentration of an analyte in a fluid sample, such as blood.

Abstract: A chemiluminescence-based gel assay may be used as an indicator of fermenter health. The assay is performed using a sample of fermentation medium essentially directly from the fermenter (with no need for complicated purification of the sample before performing the assay). Results from the assay may be correlated with the final product purification yield of a given protein/purification protocol system. This may then be used as a predictor of purification yield before actually performing the purification.

Abstract: A process for purifying thrombin-like proteases from snake venoms is described, which consists in freeing the proteases from impurities in three chromatographic steps: a) affinity or anion exchange, b) adsorption onto a glass matrix at alkaline pH values, and c) size exclusion gel or glass matrix at acidic pH values.

Abstract: A purified enzyme-I is obtained that participates in C-terminal amidation by acting on a peptide C-terminal glycine adduct to form a peptide C-terminal .alpha.-hydroxyglycine adduct. The enzyme has an optimum pH of about 5 to 7, an optimum temperature of 25 to 40.degree. C. and a molecular weight of about 25 kDa or about 36 kDa, and metal ions and ascorbic acid act as a cofactor. A purified enzyme-II is obtained that participates in C-terminal amidation by acting on the peptide C-terminal .alpha.-hydroxyglycine adduct to produce a C-terminal amidated compound. The enzyme has an optimum pH of about 5 to 6, an optimum temperature of 15 to 35.degree. C. and a molecular weight of about 40 kDa or about 43 kDa. Enzyme-I does not act on the peptide C-terminal .alpha.-hydroxyglycine adduct and enzyme-II does not act on the peptide C-terminal glycine adduct. The enzymes may be purified from a biological material such as horse serum by affinity chromatography using a peptide C-terminal glycine adduct as a ligand.

Abstract: A peptide such as in a cell-free fermentation medium is ultrafiltered with a membrane having a molecular weight cut-off of at least approximately two times greater than the molecular weight of the peptide. The peptide is retained by the membrane, and is desalinated and concentrated to provide prepurification of the peptide. A preferred temperature for ultrafiltration is about 5 to about 15.degree. C. Permeate flow rate may be about 10 l/m.sup.2 /h to about 35 l/m.sup.2 /h, and permeate conductivity may be less than about 10 mS/cm. The permeate may be recycled until peptide concentration is constant. A cell-free fermentation medium containing hirudin from a recombinant microorganism such as Saccharomyces cerevisiae is ultrafiltered with a membrane having a molecular weight cut-off of about 20 kD to about 30 kD.

Abstract: A method is presented for inactivating undesired acid labile proteases which are expressed into the culture medium simultaneously with desired enzymes by Aspergillus species when Aspergillus species is used as the host for recombinantly producing enzymes. The method involves incubating culture medium which contains a mixture of the desired recombinantly produced enzyme and the undesired acid labile protease which have been expressed therein at pH values below 4.5 and at temperatures from 2.degree. C. to 75.degree. C. for at least 20 seconds.