Chromatium transhydrogenase

The Chromatium transhydrogenase was isolated by Keister and Hemmes 16) from a sonicated extract of Chromatium strain D. After high-speed centrifugation and ammonium sulfate precipitation, two subsequent steps of DEAE-cellulose chromatography were employed. The purity of the preparation was tested for various reductase.and dehydrogenase activities. 

Sulfhydryl agents, e.g., p-hydroxymercuribenzoate, both inactivate and activate the Pseudomonas enzyme, depending on the presence of oxidized and reduced substrates, respectively (17). Inactivated protein may be reactivated by mercaptoethanol suggesting that p-hydroxymercuribenzo-ate acts on sulfhydryl groups near or at the active site. Reversible effects of sulfhydryl agents were also observed with the Chromatium enzyme (16). Proteolytic enzymes such as trypsin did not inactivate the Pseudomonas transhydrogenase (8). 

NADH dehydrogenase and, 189 ubiquinone reductase and, 178,182,183 Cholesterol, side chain cleavage, 83, 84-85 Choline, oxidation to betaine, 260 Choline dehydrogenase electron transport system and, 261-263 properties, 260-201 Chromatium sulfate reduction by, 281 transhydrogenase of, 54 function of, 80 molecular properties, 58, 69 purification, 55, 56 Chromium... 

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