Alternative forms of triosephosphate dehydrogenase in Chromatium

Triosephosphate dehydrogenase was purified extensively from the obligately phototrophic bacterium Chromatium. Enzyme prepared from photolithotrophically grown cells differed in several properties from enzyme prepared from photoorganotrophically grown cells. Either form of the enzyme could be transformed in vitro to the other by mild oxidation or reduction, which effected both Michaelis constants and reactive -SH contents of the proteins.