title: Interactions between metabolic intermediates and beta-galactosidase from Escherichia coli.
abstract: 1. 5-Phosphorylribose 1-pyrophosphate, in the presence of beta-mercaptoethanol, protected beta-galactosidase from heat inactivation. Many other substances, including 3':5'-cyclic-AMP, were without effect. 2. The efficiency of complementation in vitro of beta-galactosidase segments was decreased by 5-phosphorylribose 1-pyrophosphate but not by 3':5'-cyclic-AMP. Neither substance affected the activity of the complete enzyme. 3. Some indications as to the possible identity of the catabolite repression effector are presented.
mesh_terms: D000242:Cyclic AMP; D011756:Diphosphates / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D005696:Galactosidases / Q000378:metabolism*; D006358:Hot Temperature; D008623:Mercaptoethanol / Q000494:pharmacology; D011489:Protein Denaturation; D012266:Ribose
chemical_list: D011756:Diphosphates; D008623:Mercaptoethanol; D012266:Ribose; D000242:Cyclic AMP; D005696:Galactosidases