海洋双壳贝类软体动物（海神蛤属）中肠腺腺苷脱氨酶的纯化及性质

Purification and properties of the adenosine deaminase from the midgut gland of a marine bivalved mollusc, Atrina spp.

Aikawa T, Umemori-Aikawa Y, Fisher J R

Institute of Molecular Biophysics, Florida State University, Tallahassee 32306.

Comp Biochem Physiol B. 1977;58(4):357-64. doi: 10.1016/0305-0491(77)90182-1.

Abstract

The adenosine deaminase has an approximate molecular weight of 130,000-140,000 and the composition of two polypeptide units (mol. wt about 68,000) is suggested, by means of SDS disc electrophoresis. 2. Both the alpha (Vm/Km) and beta (Vm) parameters were varied with pH and temperature. RSS (relative substrate specificity) adenosine and deoxyadenosine values for alpha and beta were 1.2 and 1.1, respectively. 3. Adenine, 2'-, 3', 5'-AMP, 5'-deoxyAMP, ADP and ATP were not deaminated by the enzyme. 4. Inhibition by Mg2+ was found in reaction with adenosine at pH 8 but not with deoxyadenosine at the same pH. Mn2+, which did not affect the reaction rate at pH 4 and 5, showed competitive inhibitory effects at pH 6, 7 and 8.

摘要

腺苷脱氨酶的分子量约为130,000 - 140,000，通过SDS圆盘电泳表明其由两个多肽单元（分子量约68,000）组成。2. α（Vm/Km）和β（Vm）参数均随pH值和温度而变化。α和β的相对底物特异性（RSS）腺苷和脱氧腺苷值分别为1.2和1.1。3. 腺嘌呤、2'-、3'、5'-AMP、5'-脱氧AMP、ADP和ATP均不能被该酶脱氨。4. 发现在pH 8时与腺苷反应中Mg2+有抑制作用，但在相同pH下与脱氧腺苷反应时则无。Mn2+在pH 4和5时不影响反应速率，但在pH 6、7和8时表现出竞争性抑制作用。