Nitric oxide causes inactivation of the low molecular weight phosphotyrosine protein phosphatase.

摘要: The low M(r) phosphotyrosine protein phosphatase (PTPase) and Yersinia enterocolitica PTPase are inactivated by nitric oxide-generating compounds. Inorganic phosphate, a competitive inhibitor, protects the enzymes from inactivation, suggesting that action of NO is directed to active sites. Low bovine liver lost two out eight thiol groups present in molecule during inactivation with sodium nitroprusside other NO-producing mass spectrometric analyses tryptic fragments enzyme, performed after chemical modification NO-unreacted groups, demonstrated caused oxidation Cys-12 Cys-17 form an S-S bond. A similar reaction was described previously for N-methyl-D-aspartate receptor. NO-inactivated reactivated treating inactive enzyme thiol-containing reagents. Since all members family have same mechanism possess conserved site motif contains essential cysteine residue, findings on PTPases potentially interesting PTPases, class involved number important biological processes.