Formation of Trivalent Cobalt Complexes in Protein Hydrolysates

Abstract

E. LESTER SMITH¹, and later E. L. Rickes et al.², have reported that the pure anti-pernicious anæmia principle (vitamin B₁₂) isolated by them^3,4 was a cobalt complex, containing as much as 4 per cent cobalt dry weight. Immediately after we had been informed about this extraordinary fact by Dr. Lester Smith of Glaxo Laboratories⁵, we started the present investigation. We were able first to show that all the amino-acids available to us (see table), with the exception of tryptophane, when treated with cobalt (II) chloride and hydrogen peroxide under suitable conditions, gave solutions the colour of which showed much resemblance to that of a sample of Lester Smith's preparation.