PF1556 pth Peptidyl-tRNA hydrolase The natural substrate for this enzyme may be peptidyl- tRNAs which drop off the ribosome during protein synthesis (By similarity). 119 PTH_PYRFU MGFRYKQVIVARSDLKLSKGKLAVQVAHGAVTAAFEAYKKKREWFEAWFREGQKKVVVKAQNEEELFKLKSEAEKLGLPTALIRDAGLTEIPPGTITVLAIGPGPEEVVDKVTGHLKLL