The cytotoxin α‐sarcin behaves as a cyclizing ribonuclease

FEBS Letters

Mancheño, José M¹  Oñaderra, Mercedes¹  Lacadena, Javier¹  Martı́nez-Ruiz, Antonio¹  Lacadena, Valle¹  Gavilanes, José G¹  Martı́nez del Pozo, Alvaro¹ 

[1] Departamento de Bioquı́mica y Biologı́a Molecular I, Facultad de Quı́mica, Universidad Complutense de Madrid, 28040 Madrid, Spain

关键词: Dinucleotide;    Ribonucleolytic activity;    Ribosome-inactivating protein;    Ribotoxin;    2′-AMP;    adenosine 2′-monophosphate;    3′-AMP;    adenosine 3′-monophosphate;    2′(3′)-AMP;    adenosine 2′- and 3′-monophosphate (mixed isomers);    ApA;    adenylyl(3′→5′)adenosine;    2′;    3′-cAMP;    adenosine 2′;    3′ cyclic monophosphate;    3′-GMP;    guanosine 3′-monophosphate;    2′;    3′-cGMP;    guanosine 2′;    3′ cyclic monophosphate;    GpA;    guanylyl(3′→5′)adenosine;    poly(A);    polyadenylic acid;    RNase A;    bovine pancreatic ribonuclease A;    RNase T1;    ribonuclease T1 from Aspergillus oryzae;   

DOI  :  10.1016/S0014-5793(98)00137-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The hydrolysis of adenylyl(3′→5′)adenosine (ApA) and guanylyl(3′→5′)adenosine (GpA) dinucleotides by the cytotoxic protein α-sarcin has been studied. Quantitative analysis of the reaction has been performed through reverse-phase chromatographic (HPLC) separation of the resulting products. The hydrolysis of the 3′-5′ phosphodiester bond of these substrates yields the 2′-3′ cyclic mononucleotide; this intermediate is converted into the corresponding 3′-monophosphate derivative as the final product of the reaction. The values of the apparent Michaelis constant (K _M), k _cat and k _cat/K _M have also been calculated. The obtained results fit into a two-step mechanism for the enzymatic activity of α-sarcin and allow to consider this protein as a cyclizing RNase.

【 授权许可】

Unknown