DETECTION OF HISTIDINE-PHOSPHO-PROTEINS IN ANIMAL-TISSUES

In this report we outline a protocol for rapid detection of histidine phosphoproteins in cellular crude extracts prepared from different tis sues. The nature of the phosphorylated amino acid residues was confirm ed by determination of their stability under different pH conditions a nd by direct phospho-amino acid analysis. Furthermore, DEPC treatment that can selectively modify the histidine residues blocks the phosphor ylation. Interestingly, the phosphoprotein pattern detected under thes e conditions in four different tissues is very similar, suggesting tha t these proteins play important roles in biochemical pathways shared b y many cells and tissues.