Abstract: A method for the selective determination of sialic acid-carrying glycolipid complexes in blood, in which the serum is diluted with water, then extracted with a water-immiscible organic solvent or solvent mixture to remove neutral lipids, a lipoprotein fraction containing sialic acid-carrying glycolipids is precipitated from the aqueous phase, the precipitated fraction is redissolved, and the sialic acid content of the solution or the amount and quality of the sialic acid-carrying glycolipid are determined by a method known per se. A water-soluble salt of a monovalent, bivalent or trivalent metal other than alkali metal is used as a precipitating agent in an amount corresponding to a final metal ion concentration of 0.005-0.1 mole/l in the mixture, and precipitation is performed at a pH of 1.5 to 8.0.

Abstract: Glucoamylase is immobilized with a carbodiimide on a polymer having amino or carboxy functional groups. When the polymer contains amino groups, the glucoamylase is treated with the carbodiimide and then mixed with the polymer or the carbodiimide is added to a mixture of the glucoamylase and the polymer. When the polymer contains carboxy groups, the polymer is treated with the carbodimide and then mixed with the glucomylase. The polymer is produced from acrylic acid, metharylic acid, acrylamide, methacrylamide, N-amino-ethyl-acrylamide and/or N-amino ethyl methacrylamide and a cross-linking agent of the acrylic or allylic type.

Abstract: The invention relates to a process for the immobilization of compounds comprising nucleophilic groups.According to the process of the invention a polymer comprising an amido group is swollen in a buffer. For this purpose any buffer is suitable which contains no amino, sulfhydryl and/or hydroxy groups in the molecule. To the swollen polymer a solution of a quinone - preferably p-benzoquinone - in a water miscible organic solvent is added and the mixture is activated at 273.degree.-343.degree. K. for 0.5-48 hours - preferably for 24 hours. The unreacted quinone is washed out with an aqueous solution of a water miscible organic solvent and thereafter water and/or a buffer. To the purified gel at a pH value between 3 and 11 - preferably between 6 and 8 - a buffered solution of a compound comprising a nucleophilic group is added, the suspension is incubated at 260.degree.-313.degree. K. for 24 hours, the gel is separated and the non-bound compound comprising a nucleophilic group is removed by washing.

Abstract: Carboxypeptidase B enzyme is isolated by a process wherein homogenized and autolyzed pancreas is subjected to a thermal treatment, and carboxypeptidase B is separated by fractionation with ammonium sulfate. This process produces carboxypeptidase B having satisfactory specific activity while eliminating the use of pancreas cell fluid or an acetonous powder from pancreas as a starting material. The isolated carboxypeptidase B may be immobilized on a polymer gel containing carboxy groups activated with a carbodiimide.

Abstract: Immobilized aminoacylase having high specific activity is obtained by covalent bonding of aminoacylase to a partially hydrolyzed Akrilex P type acrylamide-N,N.sup.1 -methylene-bis (acrylamide) copolymer. Covalent bonding is carried out by partially hydrolyzing the copolymer with a base or an acid to form carboxy groups, activating the carboxy groups with a carbodiimide and coupling aminoacylase to the activated carboxy groups. The aminoacylase may be isolated from mammal kidneys by forming an aqueous kidney extract, heat treating the extract and isolating aminoacylase from the heat treated extract.

Abstract: Immobilized cholinesterase enzyme preparations are prepared by treating a polymeric resin, built up from acrylic acid and/or methacrylic acid and acryl amide and/or methacryl amide monomers with an acryl or allyl type cross-linking agent and containing at least 0.1 meq/g of --COOH functional groups, with a carbodiimide derivative which is soluble in water or is soluble in an organic solvent at temperatures below 0.degree. C., applying a solution of cholinesterase enzyme with a pH of 4.5 to 8.5 to the resulting activated support, washing the resulting product, and drying it if desired.

Abstract: Aminoacylase is isolated from mammal kidneys by comminuting and homogenizing mammal kidney in water, centrifuging to form an aqueous extract, heating the aqueous extract at 60.degree. to 80.degree. C. for 5 to 15 minutes, centrifuging, adding a salt such as ammonium sulfate to the resultant supernatant, centrifuging to separate solids, dissolving the solids in water, dialyzing and recovering active aminoacylase from the dialyzed solution. The process produces aminoacylase with high specific activity and the process requires fewer purification steps. The aminoacylase obtained may be utilized directly without any subsequent purification to produce immonobilized aminoacylase. Immobilization can be carried out by covalent bonding of the aminoacylase to a partially hydrolyzed Akrilex P type acryl amide-N,N'-methylene-bis(arylamide) copolymer. The recovered aminoacylase can be subjected to two chromatographic purification steps to produce a very pure aminoacylase.