Nitrate reductase Chlorella vulgaris

Chlorella vulgaris nitrate reductase structure, 3,1438 Chlorides... 

Cerium tetrakis(acetylacetonate), 1114 Cesium complexes crown ethers, 40 Chevrel phases, 1321 Chlorella vulgaris nitrate reductase structure, 1438 Chlorine cations... 

Both assimilatory and dissimilatory nitrate reductases are molybdoenzymes, which bind nitrate at the molybdenum. EXAFS studies1050 have shown that there are structural differences between the assimilatory nitrate reductase from Chlorella vulgaris and the dissimilatory enzyme from E. coli. The Chlorella enzyme strongly resembles sulfite oxidase1050,1053 and shuttles between mon-and di-oxo forms, suggesting an oxo-transfer mechanism for reduction of nitrate. This does not appear to be the case for the E. coli enzyme, for which an oxo-transfer mechanism seems to be unlikely. The E. coli enzyme probably involves an electron transfer and protonation mechanism for the reduction of nitrate.1056 It is noteworthy that the EXAFS study on the E. coli nitrate reductase showed a long-distance interaction with what could be an electron-transfer subunit. 

The postulated catalytic cycles for pterin-containing molybdenum enzymes involve a two-electron change at the molybdenum atom (Mo(VI) Mo(IV)). Microcoulometric titrations of nitrate reductase Chlorella vulgaris) (76), milk xanthine oxidase (77), and sulfite oxidase (78) show that their molybdenum centers are reduced by two electrons. The reduction potentials for the molybdenum center of chicken liver sulfite oxidase are strongly dependent upon pH and upon anion concentration (78). 

Nitrate reductase (assimilatory) Chlorella vulgaris 360000 4 4 heme, 4FAD... 

Lorimer, G. H., Gewitz, H., Volker, W., Solomonson, L. P. and Vennesland, B. (1974) The presence of bound cyanide in the naturally inactivated form of nitrate reductase of Chlorella vulgaris. J. Bioi. Chem. 249, 6074-6079. 

Properties of Chlorella vulgaris and Some Higher Plant Nitrate Reductases (NRs)... 

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