Relationship of Vitamin B 6 to the Met ∗

Summary

Homogenized kidney from rats deficient in vitamin B₆ exhibited only one third as much D-amino acid oxidase activity as did normal rat kidney homogenates. However, when the food intake of control animals was restricted to that of the B₆ dieficient group there was no significant difference between the two groups in their kidney D-amino acid oxidase activity.

A gavage supplement of D-amino acids (leucine, isoleucine, phenylalanine and valine) to vitamin B₆ deficient rats greatly depresses dietary nitrogen utilization. Simultaneous injection of, or an adequate dietary supply of, vitamin B₆ completely overcomes this effect.

Supplements of the L-isomers of the same amino acids or an equivalent amount of inorganic nitrogen effected a smaller depression of dietary nitrogen utilization, thus pointing to a specific relationship between D-amino acid metabolism and vitamin B_6.