Isoenzyme and protein patterns of pentose-fermenting yeasts

Abstract
Soluble proteins were extracted from the vegetative cells of four pentose-fermenting yeasts, Candida shehatae, Pichia stipitis, R-1, and R-2, the R strains being of uncertain taxonomy, while the other two are culture collection yeasts. Isoenzyme patterns, protein patterns, and two-dimensional polypeptide mapping of these four strains were compared by polyacrylamide gel electrophoresis. The two R strains showed great similarity in two-dimensional polypeptide mapping, the pattern of sodium dodecyl sulfate – polyacrylamide gel electrophoresis, isoelectrofocusing, and isoenzymes, and may be one species. Each of the other two yeasts had its own characteristic electrophoretic pattern. The R strains showed the presence of three alcohol dehydrogenase isoenzymes compared with one for the culture collection yeasts, as well as much higher activity of malate dehydrogenase, isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase, which further the formation of pyruvate and ethanol.