Component of the EKC/KEOPS complex that is required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine. The complex is probably involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37. Tprkb acts as an allosteric effector that regulates the t(6)A activity of the complex. Component of the EKC/KEOPS complex. Embryos display primary microcephaly, leading to early lethality (PubMed:29346415, PubMed:28805828). Marked apoptosis is observed in the brain (telencephalon) (PubMed:28805828). Fishes do not show a renal phenotype, possibly as a result of early lethality (PubMed:28805828). Belongs to the CGI121/TPRKB family.