RESOLUTION OF RACEMIC PHENYLALANINE, TYROSINE, AND TRYPTOPHAN

Resolution of racemic phenylalanine, tyrosine, and tryptophan.

Resolution of racemic phenylalanine.

Phenylalanine has previously been resolved by fractional crystallization of the brucine salt of formyl-nn-phenylalanine (1) or of the cinchonine salt of benzoyl-nn-phenylalanine (2). Enzymatic methods have also been used for the resolution. According to the method of Gilbert, Price, and Greenstein (3), racemic phenylalanine is resolved by subjecting its Nchloroacetylated derivative to asymmetri...

Phenylalanine Hydroxylase, Tyrosine Hydroxylase, and Tryptophan Hydroxylase

Liquid-chromatographic quantification of plasma phenylalanine, tyrosine, and tryptophan.

Phenylalanine, tyrosine, and tryptophan are isolated and quantified by "high-pressure" liquid chromatography, with fluorescence detection. An isocratic mobile phase and reversed-phase column are used to provide rapid and reproducible measurement of these amino acids in as little as 1 to 2 microL of human plasma.

Regulatory properties of phenylalanine, tyrosine and tryptophan hydroxylases.

I have previously discussed the idea that the three pterindependent enzymes, phenylalanine (EC 1.14.16. I ) , tyrosine (EC 1.14.16.2) and tryptophan hydroxylase (EC 1.14.16.4), constitute a family of enzymes whose individual members share many properties, both physical and catalytic (Kaufman, 1974). This notion has predictive value since there have been many instances where the discovery of a r...