The Relation of Pteroylglutamic Acid to Metal-Porphyrin Enzymes.

Abstract

Streptococcus faccalis was grown in the usual PGA-deficient medium containing graded amounts of PGA, to which either 0.05% potassium cyanide, 0.5% caffeine, or 0.012% hydrogen peroxide was added as an inhibitor. The inhibition induced by any of these three substances was partially reversed by large amounts of PGA. In control experiments where the Ca pantothenate content of the medium was varied but the PGA content kept constant, no such reversal of inhibition was found even with high levels of Capantothenate. these data lend additional support to the suggestion that PGA is involved in thc synthesis of the porphyrin portions of metal-porphyrin enzymes.