title: Studies on glucose isomerase from a Streptomyces species.
abstract: Production and properties of glucose isomerase from a Co2+-sensitive Streptomyces species were studied. After 4 days of shaking cultivation at 30 degrees C and 200 rpm, a maximum of 1.1 enzyme units per ml of broth was obtained. Cell-free glucose isomerase, obtained from mycelia heat-treated in the presence of 0.5 mM Co2+, showed a 3.5-fold increase in specific activity over enzyme obtained from untreated mycelia. The optimum pH and temperature for the glucose isomerase were 7 to 8 and 80 degrees C, respectively. The Michaelis constant for fructose was 0.40 M. Mg2+ was found to enhance the glucose isomerase activity, whereas the effect of Co2+ on enzyme activity depended on the manner in which the enzyme was prepared. This glucose isomerase was quite heat stable, with a half-life of 120 h at 70 degrees C.
mesh_terms: D002238:Carbohydrate Epimerases / Q000096:biosynthesis / Q000378:metabolism; D003035:Cobalt / Q000494:pharmacology; D005632:Fructose / Q000096:biosynthesis; D005947:Glucose / Q000378:metabolism; D006358:Hot Temperature; D008274:Magnesium / Q000494:pharmacology; D013302:Streptomyces / Q000201:enzymology*
chemical_list: D005632:Fructose; D003035:Cobalt; D002238:Carbohydrate Epimerases; D008274:Magnesium; D005947:Glucose