Processing of t-RNA: In both Eukaryotes and prokaryotes t-RNA processing occurs. It is transcribed as long precursor; sometimes single primary transcripts carry more than one t-RNA segments which are separated by cleavage. Processing of pre tRNA involves cutting off of extra sequences by endonucleases such as RNase P at 5’ end and RNase D at 3’ end. RNase P is a ribozyme with RNA exhibiting catalytic activity. After removal of sequences from 3’ end, CCA sequence is added via enzyme tRNA nucleotidyltransferase This enzyme binds to CCA sequence at its active site and phosphodiester bond is formed with 3’ end. Furthermore, there is base modification occurring simultaneously such as methylation, deamination or reduction; in case of pseudouridine, uracil is removed and reattached to sugar through C5.Processing of tRNA  is described in figure 29.7.

Figure 29.7: Processing of t-RNA