Purification and kinetic characteristics of pyruvate decarboxylase and ethanol dehydrogenase fromZymomonas mobilisin relation to ethanol production

✍ Scribed by Toni C. Hoppner; Horst W. Doelle

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 569 KB
• Volume: 17
• Category: Article
• ISSN: 1432-0614
• DOI: 10.1007/bf00505880

✦ Synopsis

Alcohol dehydrogenasc (EC 1.1.1.1) and pyruvate decarboxylase (EC 4.1.1.1) from Zymomonas mobilis were partially purified and characterized. Alcohol dehydrogenase exhibits a pH optimum at 6.5 and pyruvate decarboxylase a major peak at pH 6.0 and a minor one at pH 4.3. The molecular weights were estimated to be 147,300 + 14,700 and 219,700 + 20,400 daltons, respectively. Both enzymes exhibit hyperbolic saturation curves with their respective substrates. Whereas alcohol dehydrogenase was inhibited by ethanol (Ki = 6.86 x 10 -4 M) and NAD + (K i = 1.44 x 10 -4 M), no inhibition was observed with pyruvate decarboxylase at similar concentrations of ethanol. Neither of the enzymes responded to sulphydryl-binding reagents, but differed in their response to a number of divalent metals. The results are compared with those of the respective enzymes from yeast and discussed with a view towards ethanol production limitations by Zymomonas mobilis.