多聚磷酸盐强烈抑制由酿酒酵母的多聚（A）聚合酶催化的依赖于tRNA的多聚（A）合成。

Polyphosphates strongly inhibit the tRNA dependent synthesis of poly(A) catalyzed by poly(A) polymerase from Saccharomyces cerevisiae.

作者信息

Sillero María A Günther, de Diego Anabel, Silles Eduardo, Osorio Hugo, Sillero Antonio

机构信息

Departamento de Bioquímica, Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC, Facultad de Medicina, 28029 Madrid, Spain.

出版信息

FEBS Lett. 2003 Aug 28;550(1-3):41-5. doi: 10.1016/s0014-5793(03)00815-9.

DOI:10.1016/s0014-5793(03)00815-9

PMID:12935883

Abstract

Polyphosphates of different chain lengths (P(3), P(4), P(15), P(35)), (1 microM) inhibited 10, 60, 90 and 100%, respectively, the primer (tRNA) dependent synthesis of poly(A) catalyzed poly(A) polymerase from Saccharomyces cerevisiae. The relative inhibition evoked by p(4)A and P(4) (1 microM) was 40 and 60%, respectively, whereas 1 microM Ap(4)A was not inhibitory. P(4) and P(15) were assayed as inhibitors of the enzyme in the presence of (a) saturating tRNA and variable concentrations of ATP and (b) saturating ATP and variable concentrations of tRNA. In (a), P(4) and P(15) behaved as competitive inhibitors, with K(i) values of 0.5 microM and 0.2 microM, respectively. In addition, P(4) (at 1 microM) and P(15) (at 0.3 microM) changed the Hill coefficient (n(H)) from 1 (control) to about 1.3 and 1.6, respectively. In (b), the inhibition by P(4) and P(15) decreased V and modified only slightly the K(m) values of the enzyme towards tRNA.

摘要

不同链长的多聚磷酸盐（P(3)、P(4)、P(15)、P(35)）（1微摩尔）分别抑制了酿酒酵母中引物（tRNA）依赖性多聚腺苷酸合成所催化的多聚腺苷酸聚合酶活性的10%、60%、90%和100%。p(4)A和P(4)（1微摩尔）引起的相对抑制率分别为40%和60%，而1微摩尔的Ap(4)A没有抑制作用。在（a）饱和tRNA和不同浓度ATP存在以及（b）饱和ATP和不同浓度tRNA存在的情况下，对P(4)和P(15)作为该酶抑制剂进行了测定。在（a）中，P(4)和P(15)表现为竞争性抑制剂，其抑制常数（K(i)）值分别为0.5微摩尔和0.2微摩尔。此外，P(4)（1微摩尔）和P(15)（0.3微摩尔）分别将希尔系数（n(H)）从1（对照）改变为约1.3和1.6。在（b）中，P(4)和P(15)的抑制作用降低了酶的最大反应速度（V），并且仅轻微改变了该酶对tRNA的米氏常数（K(m)）值。