Cortay J C, Duclos B, Cozzone A J
J Mol Biol. 1986 Jan 20;187(2):305-8. doi: 10.1016/0022-2836(86)90236-6.
The analysis of protein phosphorylation in the bacterium Escherichia coli showed that, while most phosphoproteins are modified at serine and/or threonine residues, one of them is modified exclusively at tyrosine. This particular protein which has a molecular weight of 54,500 and a pHi value of 5.6 is found associated with the membrane/ribosome fraction of the cell.