鸟巢蕨的胸苷磷酸转移酶和核苷酸磷酸水解酶。一般特性及3':5'-环磷酸腺苷的抑制作用

Thymidine phosphotransferase and nucleotide phosphohydrolase of the fern Asplenium nidus. General properties and inhibition by adenosine 3':5'-cyclic monophosphate.

作者信息

Grivell A R, Jackson J F

出版信息

Biochem J. 1976 Jun 1;155(3):571-81. doi: 10.1042/bj1550571.

DOI:10.1042/bj1550571

PMID:182131

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1172879/

Abstract

Extracts of several plant species contained nucleoside-AMP phosphotransferase activity. The ratio of activity with thymidine to that with uridine as nucleoside substrate was essentially constant, both between species and throughout plant development. Evidence is presented that the total thymidine-AMP phosphotransferase activity of the leaves of Asplenium nidus (bird's-nest fern) and of Helianthus tuberosus (Jerusalem artichoke) increases during maturation. 2. Thymidine-AMP phosphotransferase was purified 22-fold from a very rich source of this activity, extracts of A. nidus. 3. A broad specificity towards both nucleoside and nucleoside 5'-monophosphate substrates is displayed by this preparation, and the evidence suggests that all could be due to a single enzyme. 4. Nucleosides that act as substrates will also inhibit phosphotransfer to other nucleosides, with Ki values close to the corresponding Km values found when utilized as substrates. 5. Ca2+-activated ATP phosphohydrolase was separated from the phosphotransferase by differential complexing to Blue Dextran in the presence of urea, whereas an AMP phosphohydrolase activity was closely associated with thymidine-AMP phosphotransferase through all separation techniques used. 6. Metal ions did not activate either of the latter two activities, and 1,10-phenanthroline was found to inhibit the phosphotransferase. 7. Km values for AMP for the respective activities were 0.11 mM (thymidine phosphotransferase) and 0.20 mM (AMP phosphohydrolase) and for thymidine (phosphotransferase only) 0.88 mM. 8. 3':5'-Cyclic AMP was found to inhibit both phosphotransferase and AMP phosphohydrolase activities, with Ki values of 0.056 mM and 0.15 mM respectively. It is suggested that this inhibitor would be of value in revealing the existence of thymidine kinase in plant extracts with high thymidine phosphotransferase activity.

摘要

几种植物物种的提取物含有核苷 - AMP磷酸转移酶活性。以胸苷为核苷底物的活性与以尿苷为核苷底物的活性之比在不同物种之间以及整个植物发育过程中基本恒定。有证据表明，鸟巢蕨和菊芋叶片中的总胸苷 - AMP磷酸转移酶活性在成熟过程中会增加。2. 从富含该活性的来源——鸟巢蕨提取物中，将胸苷 - AMP磷酸转移酶纯化了22倍。3. 该制剂对核苷和核苷5'-单磷酸底物都具有广泛的特异性，证据表明这一切可能都归因于一种单一的酶。4. 作为底物的核苷也会抑制向其他核苷的磷酸转移，其抑制常数（Ki）值接近用作底物时发现的相应米氏常数（Km）值。5. 通过在尿素存在下与蓝色葡聚糖进行差异络合，将Ca2+激活的ATP磷酸水解酶与磷酸转移酶分离，而在所有使用的分离技术中，AMP磷酸水解酶活性都与胸苷 - AMP磷酸转移酶紧密相关。6. 金属离子不会激活后两种活性中的任何一种，并且发现1,10 - 菲咯啉会抑制磷酸转移酶。7. 各自活性的AMP的米氏常数（Km）值分别为0.11 mM（胸苷磷酸转移酶）和0.20 mM（AMP磷酸水解酶），而胸苷（仅针对磷酸转移酶）的米氏常数为0.88 mM。8. 发现3':5'-环AMP会抑制磷酸转移酶和AMP磷酸水解酶活性及其抑制常数（Ki）值分别为0.056 mM和0.15 mM。有人认为这种抑制剂在揭示具有高胸苷磷酸转移酶活性的植物提取物中胸苷激酶的存在方面具有价值。