Involvement of sulfhydryl groups in the -galactosidase of Streptococcus lactis

Sulfhydryl oxidants and stabilizers caused changes demonstrating the sulfhydryl content of beta-galactosidase for Streptococcus lactis 7962. Ammonium sulfate (0.85 m) rendered the enzyme insensitive to the oxidants. Titrations revealed 11.5 moles of sulfhydryl per mole of enzyme.