AF152: Cobalamin-independent methionine synthase

List allergens from this family:

Routes of exposure:
Include only IUIS approved allergens.

Biochemical properties

Methionine synthases or 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferases from bacteria and plants catalyse the last step in the production of methionine by transferring a methyl group from 5-methyltetrahydrofolate to homocysteine. In animals, this enzyme requires Vitamin B12 (cobalamin) as a cofactor, whereas the form found in plants is cobalamin-independent. Microorganisms express both cobalamin-dependent and cobalamin-independent forms [1].

Allergens from this family

The pollen allergen Sal k 3 from Russian thistle (Salsola kali) belongs to this family. The recombinant protein bound IgE from two thirds of the tested patients [2].



  1. Hesse H, Hoefgen R:
    Molecular aspects of methionine biosynthesis.
    Trends Plant Sci 2003, 8, 259-62. [PubMed] [Full Text]
  2. Assarehzadegan MA, Sankian M, Jabbari F, Tehrani M, Falak R, Varasteh A:
    Identification of methionine synthase (Sal k 3), as a novel allergen of Salsola kali pollen.
    Mol Biol Rep 2011, 38, 65-73. [PubMed] [Full Text]


Links to Pfam

Family-defining Pfam domains (at least one of these domains is present in each family member):

Pfam domain Pfam clan
PF01717 Cobalamin-independent synthase, Catalytic domain CL0160 Cobalamin-independent synthase
PF08267 Cobalamin-independent synthase, N-terminal domain CL0160 Cobalamin-independent synthase

Links to Wikipedia


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