Journal of Food Processing & Technology

Fission yeast Schizosaccharomyces pombe?s potential role in bio-ethanol production characterisation of its hexokinase

2^nd International Conference and Exhibition on Food Technology, Bioprocess & Cell Culture

October 28-30, 2013 Kansas City Marriott Country Club Plaza, USA

Ester Mpandi Khosa

Posters: J Food Process Technol

Abstract:

The phosphorylation of hexoses in Schizosaccharomyces pombe is catalyzed by a single hexokinase. When the same method was used with Saccharomyces cerevisiae which contains two hexoskinases (PI and PII) and a glucokinase, three peaks of activity were obtained. The Schizosaccharomyces pombe enzyme has a molecular mass of about 105 kDa and is made up of two unequal subunits of molecular masses 52.5 and 47.5 kDa, whereas the molecular masses of the Saccharomyces cerevisiae enzymes are reported to be about 100 kDa and are made up of two equal subunits. The substrate specificity of the Schizosaccharomyces pombe enzyme is similar to that of the hexokinases PI and PII of Saccharomyces cerevisiae, D-glucose and D-fructose showing the highest activities. The Schizosaccharomyces pombe enzyme does not appear to be a bifunctional enzyme of the type proposed for the single hexose-ATP-kinases of Schwanniomyces occidentalis. For the Schizosaccharomyces pombe enzyme, the Km value for D-glucose was 0.05 mM and for D-fructose was 0.77 mM, values which were very similar to the values reported for the PI and PII enzymes of Saccharomyces cerevisiae. However, in a phenogram based upon amino acid composition, the hexokinase of Schizosaccharomyces pombe was only distantly related to the three enzymes of Saccharomyces cerevisiae, showing a similarity of 68.6%.