I am trying to incorporate an UAA into a protein for click chemistry. I am testing the system using BOC lysine and the Mm-PylRS-AF/Pyl-tRNACUA tRNA+synthetase pair from Addgene. The problem is, during tests comparing the pair of my plasmid of interest and the tRNA plasmid with/without BocK, there doesn't seem to be a difference between expression (full sized protein is being overexpressed at similar levels in both cases.)

Could this be due to the tRNA incorporating natural amino acids at the TAG codon, thus bypassing the supression? Does anyone have experience using this tRNA/synthetase pair?