Photodissociation of p-aminobenzoic acid at 266 nm was investigated by probing the nascent OH photoproduct employing the laser-induced fluorescence technique. It was found that the nascent OH radical was vibrationally cold and its rotational state distribution conformed to be a Boltzmann behavior, characterized by a rotational temperature of 1040±110 K. The rotational energy of OH was determine...

The fact that urethane, a structurally unrelated compound, can inhibit sulfanilamide action has caused Johnson (1942) to question the competitive metabolite hypothesis developed by McIntosh and Whitby (1939), Stamp (1939), Fildes (1940), Green (1940), Woods (1940) and Woods and Fildes (1940). He would explain the antagonism of p-aminobenzoic acid on the basis of the well-known fact that narcoti...

The biosynthesis of candicidin has been studied with various carbon-14 labeled precursors. The aromatic moiety of candicidin is evidently synthesized from glucose via shikimate to ^-aminobenzoic acid, which is then incorporated into candicidin. The synthesis of candicidin was partially inhibited by the presence of L-phenylalanine, L-tryptophane and L-tyrosine in the growing culture. The implica...

A screening method was established to detect inhibitors of the biosynthetic pathways of aromatic amino acids and para-aminobenzoic acid, the precursor of folic acid, using an agar plate diffusion assay modified as an antagonism test. By this screening method, a family of three novel polycyclic polyketides named as abyssomicins was isolated from a marine strain of Verrucosispora. The main compon...

During recent years many experiments have demonstrated the usefulness of antimetabolites for studying routes of metabolism. Competitive inhibitors have been used to block specific enzyme systems and to establish enzyme-substrate relationships, and the compounds produced by the action of these enzyme systems have been characterized through their ability to enhance the reversal of the inhibitors ...

Five new aromatic poly(amide-imide)s (5a-e) were synthesized by direct polycondensationreaction of N-(4-carboxy phenyl) trimellitimide (3) with five aromatic diamines (4a-e) by usingtriphenyl phosphite in N-methyl-2-pyrrolidone (NMP) and pyridine at solution containingdissolved CaCl2. All of the polymers were obtained in quantitative yields with inherentviscosities between 0.29-0.40 dL/g. The r...

A basis for understanding the mode of action of sulfonamide drugs in terms of the WoodsFildes theory of antagonism (Woods, 1940; Fildes, 1940) was provided by the elucidation of the structure of folic acid (Stokstad et al., 1946; Angier et al., 1946; Mowat et al., 1948). Since folic acid contains a p-aminobenzoic acid moiety, it was postulated that the structurally similar sulfonamides compete ...