11. Which of the following proteins cannot be phosphorylated using

         protein kinase in prokaryotic organisms

    A.Aspargine

   B.Cysteine

  C.Serine

  D.Methionine

Reference

Phosphorylation is found most commonly on specific serine and threonine amino acid residues in proteins, but it also occurs on tyrosine and other amino acid residues (histidine, aspartic acid, glutamic acid) as well. In most cells, about 90% of the protein phosphorylation appears on serine, 10% on threonine and ~0.05% on tyrosine residues. Therefore, protein-tyrosine phosphorylation levels appear to be about 2000-times lower than protein-serine phosphorylation levels and 200-times lower than protein-threonine phosphorylation levels. In cells like activated platelets, tyrosine phosphorylation can be orders of magnitude higher

Best option is Methionine