title: Comparative study of isoenzyme formation of bacterial beta-galactosidase.
abstract: The enzyme beta-galactosidase was studied in crude extracts of Escherichia coli 3300, E. coli grown on a selenium and sulfur medium, Salmonella typhimurium F-lac, Serratia marcescens F-lac, S. marcescens P-lac, Proteus mirabilis F-lac, P. mirabilis P-lac, Aeromonas formicans, and Streptococcus lactis. The isoenzymes could be demonstrated by an alternative histochemical technique. Different isoenzyme patterns were found to be determined by the beta-galactosidase structural gene and not by the cytoplasm within which the beta-galactosidase was formed. In addition, the beta-galactosidases from strains which form isoenzymes were more stable to heat and urea treatments than the enzyme formed by those organisms which produce reduced amounts of, or no, isoenzyme.
mesh_terms: D000179:Acrylates; D000333:Aeromonas / Q000201:enzymology; D001419:Bacteria / Q000201:enzymology*; D003470:Culture Media; D004589:Electrophoresis, Disc; D004926:Escherichia coli / Q000201:enzymology; D005696:Galactosidases / Q000032:analysis / Q000096:biosynthesis*; D005782:Gels; D007527:Isoenzymes / Q000032:analysis / Q000096:biosynthesis*; D011511:Proteus / Q000201:enzymology; D012486:Salmonella typhimurium / Q000201:enzymology; D012706:Serratia marcescens / Q000201:enzymology; D013291:Streptococcus / Q000201:enzymology; D013696:Temperature; D014508:Urea / Q000494:pharmacology
chemical_list: D000179:Acrylates; D003470:Culture Media; D005782:Gels; D007527:Isoenzymes; D014508:Urea; D005696:Galactosidases