Thermostable NAD-linked secondary alcohol dehydrogenase from propane-grown Pseudomonas fluorescens NRRL B-1244.

摘要: NAD-linked alcohol dehydrogenase activity was detected in cell-free crude extracts from various propane-grown bacteria. Two dehydrogenases, one which preferred primary alcohols (alcohol I) and another secondary II), were found Pseudomonas fluorescens NRRL B-1244 separated each other by DEAE-cellulose column chromatography. The properties of I resembled those well-known dehydrogenases. Alcohol II purified 46-fold; it homogeneous as judged acrylamide gel electrophoresis. molecular weight this is 144,500; consisted four subunits per molecule enzyme protein. It oxidized alcohols, notably, 2-propanol, 2-butanol, 2-pentanol. Primary diols also oxidized, but at a lower rate. Alcohols with more than six carbon atoms not oxidized. pH temperature optima for 8 to 9 60 70 degrees C, respectively. activation energy calculated an Arrhenius plot 8.2 kcal (ca. 34 kJ). Km values 25 7.0, X 10(-6) M NAD 8.5 10(-5) 2-propanol. inhibited strong thiol reagents metal-chelating agents such 4-hydroxymercuribenzoate, 5,5'-dithiobis(2-nitrobenzoic acid), 5-nitro-8-hydroxyquinoline, 1,10-phenanthroline. the stereoisomers 2-butanol equal had good thermal stability ability catalyze reactions high (85 C). appears have distinct previously described