| Abstrakt: |
The activity and substrate specificity of alcohol dehydrogenases (ADH) toward normal primary alcohols with different length of the carbon chain (C2--C16) was studied in the cells of the yeast Torulopsis candida. The yeast was grown in a mineral medium with various carbon substrates: glucose, pyruvate, acetate, hexadecane, cetol and palmite acid. Soluble ADHs in the cytosol fraction and ADHs bound to the fraction of membrane particles (mitochondria and microsomes, etc.) were found in the cells. Dehydration of higher alcohols (C8--C16) by the membrane fraction of cells was shown to have a relatively high rate (considerably higher than in cytosol) when the yeast was grown on hexadecane, cetol, palmitic acid and pyruvate. The membrane fraction of yeast cells prepared upon the growth on all carbon sources tested did not oxidize lower alcohols, ethanol and propanol. In contrast, upon the growth on glucose, ethanol and acetate the activity of ADH was mainly due to soluble ADHs and concentrated mainly in the cytosol fraction. Numerous molecular forms of ADH differing in their affinity for lower and higher alcohols and dependent on the growth substrate were revealed by electrophoresis in polyacrylamide gel. |
