Mutagenesis of the active site lysine 221 of the pyruvate kinase from Bacillus stearothermophilus.

Lysine 221 of the pyruvate kinase from Bacillus stearothermophilus was mutated to arginine, leucine, asparatic acid and cysteine. All the mutated enzymes were 10(4) to 10(5) times less active than the wild-type enzyme. The cysteine-free enzyme C9S/C268S, and the enzyme C9S/C268S/K221C, which possessed a unique sulfhydryl group at position 221, were prepared… CONTINUE READING