title: Lactose and melibiose metabolism in Erwinia chrysanthemi.
abstract: A Lac+ mutant of Erwinia chrysanthemi was isolated from the Lac- wild type on lactose agar. beta-Galactosidase was expressed independently of lactose transport in both the mutant and the wild type, and neither strain expressed thiogalactoside transacetylase. Lactose transport and alpha-galactosidase, constitutive in the Lac+ strain, were coordinately induced in the Lac- strain by melibiose and raffinose but not by isopropyl-beta-D-thiogalactopyranoside or thiomethyl-beta-D-galactopyranoside. Melibiose was a strong inhibitor of both the melibiose- and the raffinose-induced lactose permeases, whereas raffinose was a strong inhibitor of only the raffinose-induced lactose permease.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D004187:Disaccharides / Q000378:metabolism*; D004790:Enzyme Induction; D004885:Erwinia / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D007544:Isopropyl Thiogalactoside / Q000378:metabolism / Q000494:pharmacology; D007785:Lactose / Q000378:metabolism*; D008553:Melibiose / Q000378:metabolism* / Q000494:pharmacology; D008756:Methylgalactosides / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D011887:Raffinose / Q000494:pharmacology; D013862:Thiogalactosides / Q000378:metabolism / Q000494:pharmacology; D000519:alpha-Galactosidase / Q000378:metabolism; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D004187:Disaccharides; D008756:Methylgalactosides; D013862:Thiogalactosides; C009468:thiomethylgalactoside; D007544:Isopropyl Thiogalactoside; D008553:Melibiose; D000123:Acetyltransferases; C022770:galactoside acetyltransferase; D000519:alpha-Galactosidase; D001616:beta-Galactosidase; D007785:Lactose; D011887:Raffinose