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

FEBS Letters

de Diego, Anabel¹  Sillero, Antonio¹  Günther Sillero, Marı́a A¹  Osorio, Hugo¹  Silles, Eduardo¹ 

[1] Departamento de Bioquı́mica, Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC, Facultad de Medicina, 28029 Madrid, Spain

关键词: Poly(A) polymerase;    Polyphosphates;    Dinucleoside polyphosphates;    Saccharomyces cerevisiae;    P4;    P15;   

DOI  :  10.1016/S0014-5793(03)00815-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Polyphosphates of different chain lengths (P₃, P₄, P₁₅, P₃₅), (1 μM) 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 p₄A and P₄ (1 μM) was 40 and 60%, respectively, whereas 1 μM Ap₄A was not inhibitory. P₄ and P₁₅ 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), P₄ and P₁₅ behaved as competitive inhibitors, with K _i values of 0.5 μM and 0.2 μM, respectively. In addition, P₄ (at 1 μM) and P₁₅ (at 0.3 μM) changed the Hill coefficient (n _H) from 1 (control) to about 1.3 and 1.6, respectively. In (b), the inhibition by P₄ and P₁₅ decreased V and modified only slightly the K _m values of the enzyme towards tRNA.

【 授权许可】

Unknown