Achromobacter fischeri, nitrite reductase

VII According to Husain and Sadana (433), the earlier preparation of Achromobacter fischeri nitrite reductase with a molecular weight of... 

Achromobacter fischeri, nitrite reductase, physical properties, 277-279 Active site, lipoamide dehydrogenase, 105 Acyl hydrazides, catalase and, 379 Acyltransferase activity, glyceraldehyde-... 

Fia. 39. The absorption spectra of Achromobacter fischeri nitrite reductase. Spectra were recorded in 0.05 M phosphate buffer, pH 7.5, at 0.41 mg enzyme protcin/ml. 

VII According to Husain and Sadana (4S3), the earlier preparation of Achromobacter fischeri nitrite reductase with a molecular weight of 95,000 40,000 341) was found to be polydisperse. A monodisperse preparation subsequently studied (433) had a molecular weight of 80,000, and was shown to be composed of two subunits of approximate molecular weights of 39,000 with methionine as the sole N-terminal residue. The subunits are stated to be linked together by disulfide bridges. 

The nitrite reductase system of Achromobacter fischeri appears to be composed of two separable enzymes (341). The first enzyme is a flavin reductase and utilizes NADH or NADPH to reduce FMN or FAD. The second interacts with the flavin reductase and converts nitrite and hy-droxylaraine to ammonia. The nitrite reductase enzyme has a molecular weight of 95,000 4,000 (Table XVII), contains two heme c per mole, and is inhibited by p-mercuribenzoate, cyanide, and carbon monoxide. 

The Physical Properties of Purified Nitrite Reductase FROM Achromobacter fischeri ... 

All of the nitrite reductases just described convert NO2" to NO in a dissimilatory manner for energy extraction other nitrite reductases in assimilatory pathways convert N02 directly to NH4+ for synthetic purposes. Most of these are nonheme flavoproteins, but one has been found in Achromobacter fischeri (422) with properties similar to the dissimilatory reductases two hemes c per molecule of weight 95,000. The analogy... 

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