HomocysteineAmino AcidsHyperhomocysteinemiaSequence Homology, Amino AcidVitamin B 12Folic AcidAmino Acid SequenceMethionineAmino Acid SubstitutionHomocystineCystathionine beta-SynthaseMethylenetetrahydrofolate Reductase (NADPH2)Cloning, MolecularVitamin B ComplexVitamin B 6Betaine-Homocysteine S-MethyltransferaseCystathionineAmino Acids, Essential5-Methyltetrahydrofolate-Homocysteine S-MethyltransferaseAmino Acid Transport SystemsS-AdenosylhomocysteineSequence AlignmentOxidoreductases Acting on CH-NH Group DonorsHomocystinuriaMutationAmino Acids, SulfurBase SequenceEscherichia coliAmino Acid Motifs