MECHANISM OF INACTIVATION AND IDENTIFICATION OF SITES OF MODIFICATION OF ORNITHINE AMINOTRANSFERASE BY 4-AMINOHEX-5-YNOATE

被引:10
作者
DEBIASE, D
SIMMACO, M
BARRA, D
BOSSA, F
HEWLINS, M
JOHN, RA
机构
[1] UNIV COLL CARDIFF,COLL CARDIFF,DEPT BIOCHEM,POB 903,CARDIFF CF1 1ST,WALES
[2] UNIV LA SAPIENZA,DIPARTIMENTO SCI BIOCHIM A ROSSI FANELLI,I-00185 ROME,ITALY
[3] UNIV COLL CARDIFF,COLL CARDIFF,DEPT CHEM,CARDIFF CF1 1ST,WALES
[4] UNIV LA SAPIENZA,CNR,CTR BIOL MOLEC,I-00185 ROME,ITALY
关键词
D O I
10.1021/bi00222a029
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The inactivation of ornithine aminotransferase by an enzyme-activated irreversible inhibitor 4-aminohex-5-ynoate was accompanied by stoichiometric binding of the radiolabeled compound. Distribution of radiolabel among separated tryptic peptides indicated that more than one amino acid residue had reacted. Lys-292 and Cys-388 were positively identified. Reduction with borohydride was necessary to stabilize the adduct formed with Lys-292, and the relevant peptide prepared after this treatment contained equimolar amounts of inhibitor and coenzyme. The coenzyme chromophore in this peptide showed strong negative circular dichroism. A mechanism consistent with these observations is proposed.
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页码:2239 / 2246
页数:8
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