Pyrrolysine—tRNAPyl ligase

Pyrrolysine—tRNAPyl ligase (, PylS, pyrrolysyl-tRNA synthetase) is an enzyme with systematic name L-pyrrolysine:tRNAPyl ligase (AMP-forming). This enzyme catalyses the following chemical reaction


 * ATP + L-pyrrolysine + tRNAPyl $$\rightleftharpoons$$ AMP + diphosphate + L-pyrrolysyl-tRNAPyl

This enzyme is specific for pyrrolysine as substrate as it cannot be replaced by lysine or any of the other natural amino acids.