Tetrahydromethanopterin

Tetrahydromethanopterin (THMPT, H
4MPT) is a coenzyme in methanogenesis. It is the carrier of the C1 group as it is reduced to the methyl level, before transferring to the coenzyme M.

Tetrahydrosarcinapterin (THSPT, H
4SPT) is a modified form of THMPT, wherein a glutamyl group linked to the 2-hydroxyglutaric acid terminus.