Human erythrocytes rapidly convert vitamin B6 to pyridoxal-P and contain soluble phosphatase activity which dephosphorylates pyridoxal-P at a pH optimum of 6-6.5. This phosphatase was purified 51,000-fold with a yield of 39% by ammonium sulfate precipitation and chromatography on DEAE-Sepharose, Sephacryl S-200, hydroxylapatite, and reactive yellow 86-agarose. Sephacryl S-200 chromatography and...

2-Keto-3-methylvaleric acid (KMVA) has been found not to undergo spontaneous keto-enol tautomerization in neutral aqueous solution, alone or in the presence of large concentrations of pyridoxamine or pyridoxamine-5-phosphate. This finding denies the commonly held suppositions that 3R-KMVA is derived spontaneously from 3S-KMVA in vivo, and that L-alloisoleucine is the product of the reamination ...

To understand the processes involved in the catalytic mechanism of pyridoxal kinase (PLK),1 we determined the crystal structures of PLK.AMP-PCP-pyridoxamine, PLK.ADP.PLP, and PLK.ADP complexes. Comparisons of these structures have revealed that PLK exhibits different conformations during its catalytic process. After the binding of AMP-PCP (an analogue that replaced ATP) and pyridoxamine to PLK,...

Rogosa, Tittsler, and Geib (1947) reported that many strains of Lactobacilluss bulgaricus, Lactobacillus lactis, Lactobacillus acidophtlus, Lactobacillus delbrueckii, and Lactobacillus leichmannii failed to grow in semisynthetic media similar to those used for vitamin assay with other lactic acid bacteria, even though all of the then known B vitamins were added. Since that time oleic acid (Will...

BACKGROUND Although many studies have reported reduced vitamin B-6 status with aging, little information is available about the specific effects of menopause. OBJECTIVE We aimed to examine vitamin B-6 metabolism in premenopausal and early postmenopausal women. DESIGN We examined dietary intake and vitamin B-6 metabolites in the plasma, erythrocytes, and urine of 30 premenopausal women (x +/...

The reactions occurring when glutamate-1-semialdehyde amino-transferase (glutamate-1-semialdehyde 2,1 aminomutase, EC 5.4.3.8) was treated with two potential mechanism-based inactivators, namely 4-aminohex-5-enoate and 4-aminohex-5-ynoate, have been investigated by monitoring rapid transient changes in the absorption spectrum of the enzyme's prosthetic group, pyridoxal 5'-phosphate. In both cas...

By nonenzymatic model reactions, the influence o f vanadium (V 0 2+, V 0 3~) and other metal ions (A l3+, Fe2+, Fe3+, Zn2+, N i2+, Cr3+) on the transamination of 4,5-dioxovaleric acid (D O VA) with L-alanine (A la ) to 6 -aminolevulinic acid (<5-ALA) and pyruvic acid (P A ) with pyridoxal phosphate (P L P ) is investigated. The examinations o f the partial reactions show that V 0 2+, V 0 3~ and...