Enzymatic Determination of L-Phenylalanine and L-Tyrosine

Dual enzymatic routes to L-tyrosine and L-phenylalanine via pretyrosine in Pseudomonas aeruginosa.

Pretyrosine, an intermediate of L-tyrosine biosynthesis in blue-green algae, was found to be enzymatically formed and utilized in Pseudomonas aeruginosa. The enzymology and regulation of aromatic biosynthesis were re-evaluated in the context of these new findings, Four species of aromatic aminotranaferase were separated and partially purified. Each was reactive with prephenate, phenylpyruvate, ...

L-Phenylalanine and L-tyrosine catabolism by selected Streptomyces species.

L-Phenylalanine and L-tyrosine were completely catabolized through homogentisate by Streptomyces setonii 75Vi2 but only partially degraded by Streptomyces badius 252, Streptomyces sioyaensis P5, Streptomyces viridosporus T7A, and Streptomyces sp. strain V7. Intermediates of catabolism were confirmed by thin-layer, gas, and high-pressure liquid chromatography. Homogentisate 1,2-dioxygenase was p...

The synthesis and the enzymatic degradation of l-tyrosyl-l-lysyl-l-glutamyl-l-tyrosine.

The formation of angiotonin from the serum protein fraction art-globulin and renin (1, 2) as well as its inactivation by proteolytic enzymes suggests that this pressor substance contains peptide linkages. Preliminary studies and interpretations (3) of the action of crystalline proteolytic enzymes led to the conclusion that angiotonin contains groupings of which the simplest representation is af...

l-Phenylalanine Ammonia-Lyase (Maize): Evidence for a Common Catalytic Site for l-Phenylalanine and l-Tyrosine.

l-Phenylalanine ammonia-lyase (E.C. 4.3.1.5) from maize is active with l-tyrosine and l-phenylalanine and exhibits atypical Michaelis-Menten kinetics with both substrates. With phenylalanine as a substrate, the pH optimum is 8.7 and with tyrosine, 7.7. The estimated Km at high substrate concentrations is 0.27 mm for phenylalanine and 0.029 mm for tyrosine. However, the V(max) with phenylalanine...

University of Groningen Biosynthesis of L-Phenylalanine and L-Tyrosine in the Actinomycete Amycolatopsis methanolica