title: Induction of beta-galactosidase in Streptomyces violaceus.
abstract: Synthesis of beta-galactosidase by Streptomyces violaceus was induced by D-galactose and L-arabinose, and to a lesser extent by lactose, D-arabinose, and methyl-beta-D-galactopyranoside. The synthesis of the enzyme was linear and started to increase 2--3 h after induction by galactose, reaching a maximum after 5--7 h. The highest level of specific activity was observed in 2% galactose, with an increase of 45 times over the basal level in glycerol. Isopropyl-beta-D-thiogalactopyranoside (IPTG) and methyl-beta-D-thiogalactopyranoside (TMG) inhibited induction by D-galactose, but did not influence enzymatic activity. Cellular extracts hydrolyzed O-nitrophenyl-beta-D-galactopyranoside, but did not significantly hydrolyze lactose, melibiose, p-nitrophenyl-alpha-D-galactopyranoside, p-nitrophenyl-beta-D-fucoside, or p-nitrophenyl-beta-D-glucopyranoside. Rifampicin and chloramphenicol inhibited beta-galactosidase synthesis in non-preinduced and in preinduced cells. The inhibition by chloramphenicol was reversible.
mesh_terms: D001089:Arabinose / Q000378:metabolism; D002701:Chloramphenicol / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005690:Galactose / Q000378:metabolism; D005696:Galactosidases / Q000096:biosynthesis*; D007785:Lactose / Q000378:metabolism; D008756:Methylgalactosides / Q000378:metabolism; D012293:Rifampin / Q000494:pharmacology; D013237:Stereoisomerism; D013302:Streptomyces / Q000201:enzymology* / Q000378:metabolism; D001616:beta-Galactosidase / Q000096:biosynthesis*
chemical_list: D008756:Methylgalactosides; D002701:Chloramphenicol; D001089:Arabinose; D005696:Galactosidases; D001616:beta-Galactosidase; D007785:Lactose; D012293:Rifampin; D005690:Galactose