Replacement of lysine144 by glutamine in the pentose phosphate pathway enzyme transaldolase of Saccharomyces cerevisiae is associated with the complete loss of activity indicating the essential role in catalysis. Neither histidine nor cysteine is important for catalytic activity as proposed for the Candida utilis enzyme. Also we could not find any evidence for a half-site character of the enzyme as described for transaldolase of C. utilis. Therefore, the reaction mechanisms for the two enzymes are different.

No abstract