Interrelationship between thioctic acid, L-lyxoflavin, and riboflavin in Streptococcus faecalis.

Stokstad and Pierce (1952) presented evidence that protogen revers the inhibition of propionate for Streptococcus faecalis. IAter Brockman et al. (1952) determined the structure of protogen. Bullock et al. (1952) synthesized protogen and various closely related compounds having the property of reversing the inhibition of propionate for S. faecalis and suggested the general name, thioctic acid, for these compounds. Protogen has been identified (Snell and Broquist, 1949) with the acetate replacing factor of Guirard et al. (1946) and the pyruvate-oxidation factor of O'Kane and Gunsalus (1948). O'Kane and Gunsalus (1948) and O'Kane (1950) found that the absence of pyruvate-oxidation factor prevented the formation of acetate from pyruvate. Hill (1952) found that acetate would overcome completely the inhibition of propionate for S. faecalU and presented evidence indicating that the mechanism of propionate inhibition may be related to the formation of a propionate-coenzyme A complex which retards the formation of acetylcoensyme A, the active acetate moiety. Lipna (1939) has shown that the conversion of pyruvate to acetate by lactic acid bacteria requires a flavin component. Recently Shorb (1952) presented evidence that under certain conditions ilyxoflavin competitively ihibited riboflavin in the growth of Lactobacillus casei. -Lyxoflavin is a naturally occurring isomer of riboflavin, having been isolated first from human myocardium by Pallares and Garza (1949). The purpose of the studies presented in this report was to investigate the posible interrelationship between thioctic acid, ilyxoflavin, and riboflavin in the acetate metabolism of S. faecalis.