The Comparative Biochemistry of Vitamin Function

Abstract

The vits. may be divided into 2 natural groups, the vits. of the B-complex and vits. A, D, E, K, and C. The concn. of the members of the 1st group in the tissues varies with the metabolic activity of the tissue. Plot of the tissue or blood concn. of members of this group as a function of the log of body weight, or of O2 consumption/unit tissue weight/unit time indicates a definite correlation between the vit. concn. and these parameters of metabolic activity. When the distr. of thiamine is considered in this light, species fall into 3 major groups: the cold-blooded animals and green plants, with about 10 [mu]g.; the warm blooded animals with about 1 ug.; and the bacteria with from 0.001 to 0.01 [mu]g. of thiamine/g. of wet tissue/ml. of O2 consumed/g. of tissue/hr. With such rough conversion factors it is possible to calculate, to within 50%, the thiamine content of widely diversified species. The 2d group of the vits. show no such correlation with metabolic parameters. Other relationships are indicated, all of which are predictable from the well-known intimate association of B-complex vits. with the fundamental metabolic apparatus of living cells.