Lipoic acid as a growth stimulant for Streptococcus faecalis in the presence of limiting quantities of isoleucine and valine

Microbiological Studies With Thioctic Acid Analogues I

“…The ability of isoleucine and valine to counteract the inhibitory effect of 6-ethyl-8-mercaptooctanoic acid in T. cremoris implies that 6-ethyl-8-mercaptooctanoic acid blocks a common or similar enzymatic step on the biosynthetic pathway of these amino acids. Studies of the mechanism of biosynthesis of isoleucine and valine in microorganisms have not revealed, to date, a thioctic acid dependent step, as might be implied from the present findings; but it is of interest to note a recent report (Sheffner and Adachi, 1957) that thioctic acid was stimulatory for growth of S. faecalis in a medium in which the concentration of isoleucine and valine was limiting. lem; and also to thank Mrs. L. H. Smith for assistance with some of the microbiological testing.…”

Microbial Nutrition

“…(158), these effects are more readily observable when small inocula are used. Among the reports of the past year concerning growth stimulation is one by Sheffner & Adachi (159) showing that the addition of lipoic acid to the culture medium stimulated growth of S. faecalis in the presence of suboptimal concentrations of isoleucine, valine, and to a lesser extent arginine. Acetate did not enhance growth under these conditions.…”

Rearrangement of mitochondrial pyruvate dehydrogenase subunit dihydrolipoamide dehydrogenase protein–protein interactions by the MDM2 ligand nutlin‐3

“…The ubiquitin conjugation system has emerged as an extensive landscape of untapped potential for drug discovery . Ubiquitination can impact on protein turnover, specific‐activity, and trafficking . Ubiquitin attachment requires the concerted action of an E1, initiator ubiquitin‐activating enzyme; an E2, ubiquitin‐conjugating enzyme; and an E3, ubiquitin‐ligase adaptor that mediates ubiquitin transfer onto a substrate .…”