COMPARATIVE-STUDY OF PYRIDOXINE-ALPHA,BETA-GLUCOSIDES, AND PHOSPHOPYRIDOXYL-LYSINE AS A VITAMIN-B-6 NUTRIENT

The nutritional effects of pyridoxine-alpha-glucoside (PN-alpha-Glc), pyridoxine-5'beta-glucoside (PN-5'beta-Glc) and epsilon-N-(phosphopyri doxyl)-lysine (PNP-Lys) were examined by means of: 1) transport across the intestinal wall using everted rat intestine, 2) metabolic convers ion by liver or kidney homogenate, and 3) oral administration of the c ompound to B-6-deficient rats and the subsequent analysis of B-6 deriv atives found in plasma. Using everted sacs prepared from rat small int estine, PN-alpha-Glc was transported into the serosal side in its inta ct form. On the other hand, a part of PN-5'beta-Glc was found as PN on the serosal side (PN-5'beta-Glc: PN=2:1). When PN-alpha-Glc, PN-5'bet a-Glc or PNP-Lys was incubated with liver or kidney homogenate for 3 h at pH 6.0, PN-alpha-Glc was hydrolyzed to PN (6%), while there was no hydrolysis of PN-5'beta-Glc. After 30 min of administration of each B -6 derivative to B-6-deficient rats, blood was collected from the hear t, and the B-6-derivatives found in plasma were analyzed. It was ascer tained that PN-alpha-Glc served as well as PN as a B-6 nutrient, while PN-5'beta-Glc and PNP-Lys were not easily metabolized to the coenzyme form, pyridoxal 5'-phosphate.