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CATH Superfamily 3.20.20.330

Homocysteine-binding-like domain

The name of this superfamily has been modified since the most recent official CATH+ release (v4_2_0). At the point of the last release, this superfamily was named:

"
Homocysteine-binding-like domain
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 1039: Methylenetetrahydrofolate reductase

There are 3 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Homocysteine S-methyltransferase. [EC: 2.1.1.10]
S-methyl-L-methionine + L-homocysteine = 2 L-methionine.
  • The enzyme uses S-adenosyl-L-methionine as methyl donor less actively than S-methyl-L-methionine.
 8 A0A0T8PPH4 A0A125UG11 A0A165B5L8 A0A1B2AV63 E0U104 L8AEU0 O06745 U1ZEL5
Methylenetetrahydrofolate reductase (NAD(P)H). [EC: 1.5.1.20]
5-methyltetrahydrofolate + NAD(P)(+) = 5,10-methylenetetrahydrofolate + NAD(P)H.
  • Menadione can also serve as an electron acceptor.
  • Formerly EC 1.1.1.68, EC 1.1.1.171, EC 1.1.99.15 and EC 1.7.99.5.
 6 A0A0T8PPH4 A0A125UG11 A0A165B5L8 A0A1B2AV63 L8AEU0 O06745
Methionine synthase. [EC: 2.1.1.13]
5-methyltetrahydrofolate + L-homocysteine = tetrahydrofolate + L-methionine.
  • The enzyme becomes inactivated occasionally during its cycle by oxidation of Co(I) to Co(II).
  • Reactivation by reductive methylation is catalyzed by the enzyme itself, with S-adenosyl-L-methionine as the methyl donor and a reducing system.
  • For the mammalian enzyme, the reducing system involves NADPH and EC 1.16.1.8.
  • In bacteria, the reducing agent is flavodoxin, and no further catalyst is needed (the flavodoxin is kept in the reduced state by NADPH and EC 1.18.1.2).
  • Acts on the monoglutamate as well as the triglutamate folate, in contrast with EC 2.1.1.14, which acts only on the triglutamate.
 6 A0A0T8PPH4 A0A125UG11 A0A165B5L8 A0A1B2AV63 L8AEU0 O06745