tokens: When translated in - frame with PKC zeta , a stop codon is located 28 amino acids towards the N - terminus of the divergence point and the intervening sequence lacks an expected initiating methionine . psi PKC zeta is non - functional in terms of protein synthesis since Western blotting with an antibody directed against the C - terminus of PKC zeta failed to reveal a protein smaller than PKC zeta , and synthetic psi PKC zeta RNA failed to support protein synthesis in a translation system in vitro .