Determination of chromium combined with DNA, RNA and proteins in chromium-rich brewer's yeast by NAA

The content of chromium in the DNA, RNA and protein fractions separated fro m chromium-rich and normal brewer's yeast was determined by neutron activat ion analysis (NAA). Our results show that the extracted relative amounts an d concentrations of DNA, RNA and proteins have no significant difference fo r two types of yeast, but the chromium content in DNA, RNA and proteins fra ctions extracted from the chromium-rich yeast are substantially higher than those from the normal. In addition, the concentration of chromium in DNA i s much higher than that in RNA and proteins It is evident that the inorgani c chromium compounds can enter the yeast cell during the yeast cultivation in the chromium-containing culture medium and are converted into organic ch romium species, which are combined with DNA, RNA and proteins.