Purification and characterization of the membrane‐bound nitrate reductase isoenzymes of Bradyrhizobium japonicum

FEBS Letters

Bedmar, Eulogio J.¹  Olivares, José¹  Fernández-López, Manuel¹ 

[1] Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, P.O. Box 419, E-18080 Granada, Spain

关键词: Membrane isoenzyme;    Nitrate reductase;    Nitrate respiration;    Purification;    Bradyrhizobium japonicum;    NR;    nitrate reductase;    PAGE;    polyacrylamide gel electrophoresis;    PMSF;    phenylmethylsulfonyl fluoride;    SDS;    sodium dodecyl sulfate;    U;    activity unit(s);   

DOI  :  10.1016/0014-5793(96)00670-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Two respiratory membrane-bound nitrate reductase (NR) isoenzymes, NR_I and NR_II, have been purified for the first time from one single microorganism. Triton X-100-solubilized NRs were purified by a three-step procedure of differential centrifugation, Q-Sepharose chromatography, and gel filtration on Sephacryl S-300. Both isoenzymes were purified to homogeneity by the criteria of NR activity staining in polyacrylamide gels run under non-denaturating conditions and coincident staining of the protein band by silver nitrate. NR_I is composed of three subunits of 116 kDa, 68 kDa, and 56 kDa, whereas NR_II is composed of four subunits of 116 kDa, 68 kDa, 59 kDa, and 56 kDa. The 116-kDa subunit of NR_I and the 59-kDa subunit of NR_II exhibited immunological cross-reactivity with the respiratory NR of Pseudomonas stutzeri strain ZoBell.

【 授权许可】

Unknown