Abstract: A protein having an .alpha.-glucosidase activity, wherein its N-terminal amino acid sequence is the sequence depicted in the Sequence Listing of the present invention at Sequence No. 1; a DNA having the genetic information of the protein having an .alpha.-glucosidase activity; a recombinant vector containing said DNA; a transformant transformed with said vector; and production of .alpha.-glucosidase comprising culture of said transformant in a medium so as to grow .alpha.-glucosidase, and harvesting said .alpha.-glucosidase. According to the present invention, .alpha.-glucosidase without contamination of amylase can be easily produced in high yields and in large amounts by genetic engineering.

Abstract: The sorbitol oxidase of the present invention catalyzes the reaction in which D-sorbitol is oxidized D-glucose and hydrogen peroxide.

Abstract: A method for measuring carbon dioxide, comprising the steps of: (1) reacting bicarbonate ion in a sample with phosphoenolpyruvate carboxylase derived from an acetic acid bacterium in the presence of phosphoenolpyruvate; (2) reacting the resultant oxalacetic acid with malate dehydrogenase in the presence of NADH; and (3) measuring decreased NADH, and a reagent for measuring carbon dioxide, comprising phosphoenolpyruvate, phosphoenolpyruvate carboxylase derived from an acetic acid bacterium, malate dehydrogenase, NADH and a buffer. According to the present invention, a highly stable reagent for CO.sub.2 measurement, which permits a long-term storage in a liquid state, can be provided by the use of phosphoenolpyruvate carboxylase derived from a species of acetic acid bacteria.

Abstract: A method for determining .alpha.-amylase activity which involves bringing a sample into contact with an .alpha.-glucosidase in the presence of an .alpha.-amylase substrate and optically determining a liberated label, the substrate being a maltooligosaccharide composed of at least 3 glucose units, whose reducing terminal glucose is bonded to an optically measurable label at the 1-position by .alpha.-glucoside linkage or .beta.-glucoside linkage, and whose non-reducing terminal glucose is modified by a substituent other than glucose, and the .alpha.-glucosidase being substantially capable of acting on glucose to which the label is bonded at the 1-position by .alpha.-glucoside linkage and on all maltooligosaccharides having 2 to 7 glucose units; and a reagent for determining .alpha.-amylase activity comprising the .alpha.-glucosidase and said .alpha.-amylase substrate. The present invention permits, in the determination of .alpha.

Abstract: A protein having an .alpha.-glucosidase activity, wherein its N-terminal amino acid sequence is the sequence depicted in the Sequence Listing of the present invention at Sequence No: 1; a DNA having the genetic information of the protein having an .alpha.-glucosidase activity; a recombinant vector containing said DNA; a transformant transformed with said vector; and production of .alpha.-glucosidase comprising culture of said transformant in a medium so as to grow .alpha.-glucosidase, and harvesting said .alpha.-glucosidase. According to the present invention, .alpha.-glucosidase without contamination of amylase can be easily produced in high yields and in large amounts by genetic engineering.

Abstract: A method for measuring carbon dioxide, comprising the steps of: (1) reacting bicarbonate ion in a sample with phosphoenolpyruvate carboxylase derived from an acetic acid bacterium in the presence of phosphoenolpyruvate; (2) reacting the resultant oxalacetic acid with malate dehydrogenase in the presence of NADH; and (3) measuring decreased NADH, and a reagent for measuring carbon dioxide, comprising phosphoenolpyruvate, phosphoenolpyruvate carboxylase derived from an acetic acid bacterium, malate dehydrogenase, NADH and a buffer. According to the present invention, a highly stable reagent for CO.sub.2 measurement, permitting a long-term storage in a liquid state can be provided by the use of phosphoenolpyruvate carboxylase derived from an acetic acid bacterium.

Abstract: An isolated sorbitol oxidase from Xanthomonas maltophilia FERM BP-4512 is disclosed. The oxidase catalyzes the reaction of D-sorbitol+O.sub.2 .fwdarw.D-glucose+H.sub.2 O.sub.2, has a substrate specificity for D-sorbitol, D-mannitol, D-xylitol, and D-arabitol, has an optimum pH of 6.5 to 7.5, and has a molecular weight of 54 kD as determined by gel filtration or 43 kD as determined by SDS-PAGE. The enzyme can be used for measuring a polyol in a sample and as a reagent in a kit used for determining the presence of D-sorbitol.

Abstract: A substantially purified glucose dehydrogenase is disclosed. The enzyme has activity at a temperature of from about 30.degree. C. to about 65.degree. C. at a pH of from about pH 6 to about pH 10 and has an optimum activity at a temperature from about 50.degree. C. to about 60.degree. C. at a pH of from about 8.5 to about 9.0. The enzyme is further characterized by retaining at least 90% residual activity after treatment at 50.degree. C. for 15 minutes, being NAD or NADP dependent, having a molecular weight of about 101,000 daltons as determined by gel filtration using TSK gel, having an isoelectric point of about 4.5 by ampholyte isoelectric focusing, and having a specificity for at least .beta.-D-glucose and 2-deoxyglucose. The preferred source of the enzyme is Pseudomonas sp. FH1227.

Abstract: A new thermostable xanthine oxidase obtained from a microbe belonging to the genus Arthrobacter and a method of its production are disclosed. The present invention affords a xanthine oxidase which is excellent in thermal stability and which retains at least 70% residual activity after heat treatment at 60.degree. C. for 30 minutes. Arthrobacter luteus ATCC 21606 is the preferred microbe. The enzyme has a molecular weight of about 160,000 daltons as determined by gel filtration and a pH optimum of about 7.5.