title: Covalent modification of Escherichia coli ADPglucose synthetase with 8-azido substrate analogs.
abstract: Two photoaffinity labeling agents, 8-azido-ATP and 8-azido-ADPglucose, are substrate site specific probes of the Escherichia coli ADPglucose synthetase. In the presence of light (254 nm), the analogs specifically and covalently modify the enzyme with concomitant loss of catalytic activity. The substrate ADPglucose completely protects the enzyme from covalent modification by these 8-azido analogs. ATP, another substrate, also provides nearly 100% protection from 8-azido-ATP inactivation but is less efficient in protection of inactivation by 8-azido-ADPglucose. In the absence of light, however, ADPglucose synthetase can utilize either 8-azido-ATP or 8-azido-ADPglucose as substrates.
mesh_terms: D000245:Adenosine Diphosphate Glucose / Q000031:analogs & derivatives / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000345:Affinity Labels / Q000494:pharmacology*; D001386:Azides / Q000494:pharmacology*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D051599:Glucose-1-Phosphate Adenylyltransferase; D007700:Kinetics; D008027:Light; D009702:Nucleoside Diphosphate Sugars / Q000494:pharmacology*; D009713:Nucleotidyltransferases / Q000037:antagonists & inhibitors*; D011487:Protein Conformation
chemical_list: D000345:Affinity Labels; D001386:Azides; D009702:Nucleoside Diphosphate Sugars; C047179:8-azidoadenosine diphosphate glucose; D000245:Adenosine Diphosphate Glucose; C017040:8-azidoadenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D009713:Nucleotidyltransferases; D051599:Glucose-1-Phosphate Adenylyltransferase