title: Isolation and identification of a tyrosyl peptide labeled by 5'-[p-(fluorosulfonyl)benzoyl]-1,N6-ethenoadenosine at a GTP site of glutamate dehydrogenase.
abstract: The fluorescent nucleotide analogue 5'-[p-(fluorosulfonyl)benzoyl]-1,N6-ethenoadenosine (5'-FSB epsilon A) was shown previously to react at a GTP inhibitory site on bovine liver glutamate dehydrogenase. The incorporation was limited to 1.28 mol of reagent/mol of subunit and was attributed to 0.95 mol of modified tyrosine/mol of subunit and 0.33 mol of modified lysine/mol of subunit, quantitatively accounting for the total incorporation prior to acid hydrolysis [Jacobson, M. A., & Colman, R. F. (1983) Biochemistry 22, 4247-4257]. The specific tyrosyl peptide modified by 5'-FSB epsilon A has been isolated from a tryptic and chymotryptic digest of modified enzyme by gel filtration and reverse-phase high-performance liquid chromatography and characterized by amino acid and amino-terminal analysis. A unique residue, tyrosine-262, was identified as an essential amino acid within the GTP binding site. The stacked conformation of the fluorescent analogue when enzyme bound suggests that tyrosine-262 may be located in the region of the GTP site which binds the purine ring.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives; D000495:Allosteric Site; D000818:Animals; D002417:Cattle; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors*; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D010455:Peptides; D014443:Tyrosine
chemical_list: D010455:Peptides; D014443:Tyrosine; C010959:5'-(4-fluorosulfonylbenzoyl)adenosine; D006160:Guanosine Triphosphate; D005969:Glutamate Dehydrogenase; D000241:Adenosine