In enzymology, a tRNA nucleotidyltransferase is an enzyme that catalyzes the chemical reaction tRNAn+1 + phosphate ⇌ {\displaystyle \rightleftharpoons } tRNAn + a nucleoside diphosphatewhere tRNA-N is a product of transcription, and tRNA Nucleotidyltransferase catalyzes this cytidine-cytidine-adenosine addition to form the tRNA-NCCA product. Wikipedia