title: Vitamin B12-dependent methyltetrahydrofolate: homocysteine methyltransferase activity in normal and leukemic human hematopoietic cells.
abstract: The cyanogen bromide method was applied to the assay of vitamin B12-dependent methyltetrahydrofolate:homocysteine methyltransferase activity in normal and leukemic human hematopoietic cells. Normal peripheral lymphocytes and leukemia cells of lymphoid origin wuch as CLL and ALL, contained higher levels of enzyme activity than did normal human bone marrow cells. Normal granulocytes and leukemia cells of myeloid origin, such as CML in the chronic phase and AML, contained lower enzyme activity. Leukemia cells of CML in blast crisis showed higher mean activity than in the chronic phase of the disease.
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000097:blood*; D000328:Adult; D003488:Cyanogen Bromide; D006413:Hematopoietic System / Q000201:enzymology*; D006801:Humans; D007938:Leukemia / Q000201:enzymology*; D008780:Methyltransferases / Q000097:blood*; D014805:Vitamin B 12 / Q000502:physiology*
chemical_list: D008780:Methyltransferases; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D003488:Cyanogen Bromide; D014805:Vitamin B 12