ABSTRACT
In Candida boidinii, S-formylglutathione formed by reaction of the glutathione-dependent formaldehyde dehydrogenase is hydrolyzed to formate and glutathione by a special enzyme, S-formylglutathione hydrolase which is induced in C. boidinii along with the other enzymes of the dissimilatory pathway during growth on CH3OH. The S-formylglutathione hydrolase was purified to apparent homogeneity and a specific activity of 1390 U/mg. The molecular weight of the native enzyme was determined as 61 000 by gel filtration and 64 000 by sedimentation-diffusion equilibrium. It is composed of two nonidentical polypeptide chains of 35 000 and 25 000 daltons. The Km-value of S-formylglutathione was found to be 0.21 mM. Glutathione is a competitive inhibitor with a Ki vaue of 18.5 mM. The enzyme is very specific for S-formylglutatione, S-acetylglutathione gave 1.3%, respectively. Other glutathione derivatives of hydroxyacids tested were not split by the S-formylglutatione hydrolase.