Closely related isozymes of alcohol dehydrogenase Carboxymethylation: γ1γ1 differs widely from both β1β1 and its equine equivalence EE

FEBS Letters

Johansson, Jan²  Vallee, Bert L.¹  Jörnvall, Hans² 

[1] Center for Biochemical and Biophysical Sciences and Medicine, Harvard University, Boston, MA 02115, USA;Department of Chemistry I, Karolinska Institutet, S-10401 Stockholm, Sweden

关键词: Carboxymethylation: Protein thiol;    Isozyme;    Radiosequences analysis;   

DOI  :  10.1016/0014-5793(91)80265-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Human γ₁γ₁ alcohol dehydrogenase is quite insensitive to inactivation by iodoacetate, its equine counterpart EE highly sensitive, and the human β₁β₁ form intermediately sensitive. Imidazole hardly influences the iodoacetate inactivation of γ₁γ₁, enhances that of EE and decreases that of β₁β₁. In all isozymes metal-binding Cys residues are the most reactive, but the patterns for those binding the active site zinc atom differ. In phosphate, Cys-46 is most sensitive in EE and γ₁γ₁, Cys-174 in β₁β₁. This difference appears to correlate with the absence or presence, respectively, of an extra methyl group in the side-chain at position 48 (Ser in EE and γ₁γ₁, Thr in β₁β₁). In imidazole, the reactivity in β₁β₁ is shifted to Cys-46, while the specificity is enhanced in EE and decreased in γ₁γ₁. Thus, the inactivations illustrate large defferences among structures closely related.

【 授权许可】

Unknown