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 tissues. The nature of the phosphorylated amino acid residues was confirmed by determination of their stability under different pH conditions and by direct phospho-amino acid analysis. Furthermore, DEPC treatment that can selectively modify the histidine residues blocks the phosphorylation. Interestingly, the phosphoprotein pattern detected under these conditions in four different tissues is very similar, suggesting that these proteins play important roles in biochemical pathways shared by many cells and tissues.