腺嘌呤核苷酸对人精浆中低Km 5'-核苷酸酶的影响。

Effects of adenine nucleotides on low Km 5' nucleotidase from human seminal plasma.

Minelli A, Moroni M, Luzi L, Mezzasoma I

Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università di Perugia, Italy.

Int J Biochem. 1993 Aug;25(8):1203-7. doi: 10.1016/0020-711x(93)90600-j.

Abstract

Low Km 5' nucleotidase purified from human seminal plasma has been used in this study to investigate the response of the enzyme ot adenine nucleoside di- and triphosphates in the presence of AMP and IMP as substrates. 2. In the presence of AMP, the addition of 0.5 mM ATP to the enzyme Mg-free results into the highest Vmax/Km ratio value and other experimental combinations of effectors tested cause variation of the kinetic parameters of the enzyme, indicating a control of AMP dephosphorylation by adenine nucleotides. 3. In the presence of IMP, ATP and ADP activate the enzyme but the response to various experimental combinations of effectors shows no significant difference in the kinetic properties of the enzyme, indicating a different control of the dephosphorylation of IMP.

摘要

本研究使用从人精浆中纯化的低Km 5'核苷酸酶，以研究该酶在以AMP和IMP作为底物时对腺嘌呤核苷二磷酸和三磷酸的反应。2. 在AMP存在的情况下，向无镁的酶中添加0.5 mM ATP会导致最高的Vmax/Km比值，而测试的其他效应物实验组合会导致该酶动力学参数发生变化，表明腺嘌呤核苷酸对AMP去磷酸化有调控作用。3. 在IMP存在的情况下，ATP和ADP会激活该酶，但对各种效应物实验组合的反应表明该酶的动力学性质没有显著差异，表明对IMP去磷酸化有不同的调控作用。