TPMT2

TPMT2 is a designation used in some genome annotations to refer to a TPMT-like gene or transcript. It is considered part of the thiopurine S-methyltransferase (TPMT) family of cytosolic enzymes that catalyze the S-methylation of thiopurine drugs, contributing to their inactivation and elimination. The canonical TPMT enzyme in humans is encoded by the TPMT gene and exhibits well-characterized genetic polymorphisms that affect drug metabolism.

TPMT2, when present, may represent a paralog or alternative transcript identified in certain species or databases. Its precise expression pattern, substrate specificity, and catalytic efficiency are not universally established and may vary by organism. Where characterized, TPMT2 would be expected to share structural features with other TPMT family members, including a conserved methyltransferase fold and a SAM-dependent methylation mechanism.

Clinical relevance for TPMT2 remains unclear without specific functional or disease-association studies. Because TPMT activity influences thiopurine tolerance and toxicity, any verified TPMT2 activity or variation could, in principle, have pharmacogenetic implications, but such implications require robust evidence. Researchers and clinicians should consult organism- and transcript-specific databases and primary literature for up-to-date information on TPMT2. See also TPMT, thiopurine metabolism, and TPMT polymorphisms for broader context on this enzyme family.