Pantoylaminoethanethiol, an antagonist of pantothenic acid and pantetheine active in vitro and in the rat.

The compounds /3-d-pantoylaminoethanethiol (PAET) and the corresponding disulfide had been prepared by Barnett (1) in an attempt to find substances similar in structure to pantoyltaurine but more favorable in their inhibitory action on pantothenic acid-requiring microorganisms. Barnett showed that, although the compounds did inhibit the growth of Lactobacillus arabinosus to about the same extent as pantoyltaurine, they were not effective in protecting rats against infection with Streptococcus hemlyticus. The effect of PAET on the growth of the microorganisms was reversible by pantothenic acid. No studies on the possible antimetabolic action of the compound on the animal were reported. PAET was chosen for further studies as an antimetabolite, since a consideration of its structure suggests that it is an antagonist of pantetheine rather than of pantothenic acid itself.