In enzymology, a 5,10-methylenetetrahydromethanopterin reductase (EC 1.5.98.2) is an enzyme that catalyzes the chemical reaction

5-methyltetrahydromethanopterin + coenzyme F₄₂₀ ${\displaystyle \rightleftharpoons }$ 5,10-methylenetetrahydromethanopterin + reduced coenzyme F₄₂₀

Thus, the two substrates of this enzyme are 5-methyltetrahydromethanopterin and coenzyme F₄₂₀, whereas its two products are 5,10-methylenetetrahydromethanopterin and reduced coenzyme F₄₂₀.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with other acceptors. The systematic name of this enzyme class is 5-methyltetrahydromethanopterin:coenzyme-F420 oxidoreductase. Other names in common use include 5,10-methylenetetrahydromethanopterin cyclohydrolase, N5,N10-methylenetetrahydromethanopterin reductase, methylene-H4MPT reductase, coenzyme F420-dependent N5,N10-methenyltetrahydromethanopterin, reductase, and N5,N10-methylenetetrahydromethanopterin:coenzyme-F420 oxidoreductase. This enzyme participates in folate biosynthesis.

References

• Ma K, Thauer RK (1990). "Purification and properties of N5, N10-methylenetetrahydromethanopterin reductase from Methanobacterium thermoautotrophicum (strain Marburg)". Eur. J. Biochem. 191 (1): 187–93. doi:10.1111/j.1432-1033.1990.tb19109.x. PMID 2379499.
• GD; Geerts, WJ; Keltjens, JT; Van Der Drift, C; Vogels, GD (1991). "Purification and properties of 5,10-methylenetetrahydromethanopterin dehydrogenase and 5,10-methylenetetrahydromethanopterin reductase, two coenzyme F420-dependent enzymes, from Methanosarcina barkeri". Biochim. Biophys. Acta. 1079 (3): 293–302. doi:10.1016/0167-4838(91)90072-8. PMID 1911853.
• Ma K, Thauer RK (1990). "Single step purification of methylenetetrahydromethanopterin reductase from Methanobacterium thermoautotrophicum by specific binding to blue sepharose CL-6B". FEBS Lett. 268 (1): 59–62. doi:10.1016/0014-5793(90)80972-L. PMID 1696553. S2CID 26822476.
• Vogels GD; Hensgens, CM; Keltjens, JT; Van Der Drift, C; Vogels, GD (1990). "Purification and properties of 5,10-methylenetetrahydromethanopterin reductase, a coenzyme F420-dependent enzyme, from Methanobacterium thermoautotrophicum strain delta H". J. Biol. Chem. 265 (4): 1852–7. PMID 2298726.
• Drift C, Vogels GD (1990). "Purification and properties of 5,10-methenyltetrahydromethanopterin cyclohydrolase from Methanosarcina barkeri". J. Bacteriol. 172 (2): 564–71. doi:10.1128/jb.172.2.564-571.1990. PMC 208478. PMID 2298699.