Chiral and molecular recognition through protonation was investigated through the collision-activated dissociation (CAD) of protonated noncovalent complexes of aromatic amino acid enantiomers with l-alanine- and l-serine-containing tripeptides using a linear ion trap mass spectrometer. In the case of l-alanine-tripeptide (AAA), NH₃ loss was observed in the CAD of heterochiral H⁺(d-Trp)AAA, whil...

Phosphonopeptides based on aminomethylphosphonic acid as the C-terminal residue linked to L-amino acids possessed antibacterial activity in vitro and in vivo. Analogs in this series were generally less potent than corresponding compounds based on L-1-aminoethylphosphonic acid such as alafosfalin (L-alanyl-L-1-aminoethylphosphonic acid). Significant differences in antibacterial spectra were obse...

Zygmunt, Walter A. (Mead Johnson & Co., Evansville, Ind.). Reversal of d-cycloserine inhibition of bacterial growth by alanine. J. Bacteriol. 84:154-156. 1962.-Reversal of the antibacterial activity of d-4-amino-3-isoxazolidone by alanine in bacterial cultures actively growing on chemically defined media was compared in cultures requiring exogenous alanine and those capable of its synthesis. dl...

-Tyrosinase, tryptophanase and cysteine desulfhydrase were shown to catalyze a variety of a,—elimination, s—replacement and the reverse of the ct,—elimination reactions of amino acids. The mechanism f or these reactions was studied using the general mechanism for pyridoxal— dependent reactions. The enzyme—bound n—amino acrylate is the key intermediate. Enzymatic methods for preparing L—tyrosine...