On the multiple forms of yeast hexokinase

Abstract

Multiple forms of hexokinase have been detected by agar gel and polyacrylamide gel electro‐phoresis in crude extracts obtained from yeast cells of different strains. Electrophoretic mobility and number of enzyme forms depend on the conditions of cell disruption and vary with the respective yeast strain. Extracts from commercial baker's yeast, prepared by short‐time mechanical disruption contain two or three isozymes of hexokinase. Cell‐lysis by proteolytic procedures (toluene, extraction of dried yeast) changed the electrophoretic pattern profoundly.Between the exponential and the stationary phases of growth characteristic differences in the pattern of the two isozymes of hexokinase have been found.Five different strains of yeast revealed different patterns of hexokinase isozymes.Electrophoresis on polyacrylamide gels, using a concentration gradient of the polymer, indicated that the differences in the mobilities of these enzymes are presumably not caused by major differences in their molecular sizes. Trypsin caused an increase of electrophoretic mobility of one or both forms of the enzyme from baker's yeast.