The estimation of cocarboxylase (vitamin B1 diphosphate ester) in blood

Abstract

A mano-metric method for the rapid detn. of cocarboxylase in small samples (2 ml.) of oxalated blood is described. All the blood cocarboxylase is found within the blood cells in a combined form, the polymorphonuclear leucocytes containing more than the lymphocytes, and the non-nucleated erythrocytes containing least. Nucleated blood cells can phosphorylate vit. B1, and probably all nucleated animal cells can do so. The vit. is carried to the tissues in the free form and not as cocarboxylase. Serum contains in addition a form of unphosphorylated vit. B1 in combination with protein. The results of estimations of cocarboxylase in the blood of normal adult humans, of oxen, of sheep, and of avitaminous and normal pigeons are given. The limitations of estimations of total vit. B1 in blood as indices of the presence or absence of deficiency of the vit. are discussed.