Folic acid derivatives in the gas gland of Physalia physalis L.

Carbon monoxide is a comparative rarity among the biologically generated C, compounds. It has been found in large concentration only in the hollow stems of the kelp, Nereocy8tis (Blinks, 1951), and in the float of the Portuguese man-of-war, Phy8atia physalia L. (Wittenberg, 1958, 1960). A glandular structure, the gas gland or pneumadena, formed by localized modification of the inner wall of the float of Phy8alia, produces carbon monoxide, and will do so in vitro when supplied with L-serine. Preliminary analyses indicated that the gas gland is very rich in folates. The present work establishes that Physalia gasgland tissue is indeed the richest in folates of any animal tissue examined, and that the folates are predominantly N10-formyltetrahydro forms. N10Formyltetrahydrofolates are the known carriers of the formyl group in several biosynthetic sequences. Their very high concentration in a tissue whose specialized function is the production of carbon monoxide suggests that these folates are the precursors of carbon monoxide. If this be so, then carbon monoxide may be formed by the dehydration of a coenzyme-bound formyl fragment. In addition to the information obtained on the nature of the folates in the gas glands ,9f Phy8alia, the method presented here may serve as a prototype for the analysis of the varieties of folates occurring in other animal tissues.