Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracts of human normal and leukemic leukocytes contain an enzyme that catalyzes a transfer of labeled methyl carbon from N5-[14C]methyltetrahydrofolate to tryptamine. Evidence is presented that this reaction is not attributable to a methyltransferase but to the following reaction sequence: (a) an oxidation of N5-[14C]methyltetrahydrofolate to N5, N10-[14C]methylenetetrahydrofolate that is catalyzed by N5, N10-methylenetetrahydrofolate reductase (EC 1.1.1.68); (b) spontaneous release of [14C]formaldehyde from N5, N10-[14C]methylenetetrahydrofolate; and (c) nonenzymatic condensation of [14C]formaldehyde with tryptamine to form a radioactive carboline derivative. The occurrence of this sequence in leukocytes is suggested by data that show that the enzyme reaction is strongly stimulated by addition of flavin adenine dinucleotide and that the final product is chromatographically identical to the adduct formed in the reaction of [14C]formaldehyde with tryptamine. In the absence of tryptamine, a product accumulates that can react with other HCHO acceptors, i.e., beta-phenylethylamine and dimedone; another reaction product is tetrahydrofolate. Production of formaldehyde is relatively more active in normal lymphocytes than in normal granulocytes, but it is even higher in lymphocytes of chronic lymphocytic leukemia. Activity in granulocytes from a subject with chronic myelocytic leukemia is also elevated but to a lesser extent than activity in lymphocytes of chronic lymphocytic leukemia. Activity in granulocytes from a subject with chronic myelocytic leukemia is also elevated but to a lesser extent than activity in lymphocytes of chronic lymphocytic leukemia. Formaldehyde production in leukocytes is only slightly stimulated by addition of various cobalamins, and activity is normal in leukocytes from a vitamin B12-deficient patient. We conclude that the system is cobalamin independent. Thus, there exists an active pathway from N5-methyltetrahydrofolate to tetrahydrofolate other than the one catalyzed by cobalamin-dependent N5-methyltetrahydrofolate-homocysteine methyltransferase.
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PMID:Production of formaldehyde from N5-methyltetrahydrofolate by normal and leukemic leukocytes. 1 82

Folate-binding protein(s) from chronic myelogenous leukemia cells have been purified using acid dialysis, ammonium sulfate fractionation and affinity chromatography. The purified preparation which migrates as a single band on disc electrophoresis could be separated by DEAE agarose chromatography into two folate-binding proteins (binders I and II) which bind molar equivalents of folic acid. One binder (I) eluted from DEAE at 1 mM sodium phosphate, pH 6.0, and the other (II) at 100 mM sodium phosphate, pH 7.4. Analysis of the purified mixture, which contained more than 90% binder II, by sedimentation equilibrium centrifugation indicated a homogeneous protein with a calculated molecular weight of 44000. Antiserum raised against the purified mixture gave a single precipitin line by immunodiffusion against a preparation of partially purified cell lysate. Hydrolysis of the more acidic binder (II) with neuraminidase converted it to a weakly acidic protein similar to binder I, suggesting that these binders are glycoproteins which differ in sialic acid content. With isoelectric focusing, the binding of folic acid could be demonstrated at pH 6.7, 7.3, 7.8 and 8.2 for binder I, and at pH 5.1, 5.8, and 6.5 for binder II. Binders I and II had equally high affinity for folic acid and dihydrofolate, lower affinity for N5-methyl-tetrahydrofolate, and no apparent affinity for N5-formyltetrahydrofolate or methotrexate.
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PMID:Properties of purified folate-binding proteins from chronic myelogenous leukemia cells. 28 Mar 77

Previous studies have demonstrated that some chronic myelogenous leukemia cells contain a macromolecular binding factor for folic acid. This binder, which previously was believed to be a single factor, has now been resolved into two distinct binding proteins. Separation of each binder was obtained by DEAE chromatography of the partially purified lysate of chronic myelogenous leukemia cells. One binder has a molecular weight of 30;000-35,000, and the second binder has a molecular weight of 40,000-45,000. Both proteins bind the mono-, di-, and triglutamates of folic acid, N10-methyl-folate, dihydro-folate, and N5-methyltetrahydrofolate. Neither binder has determinants for N5-formyltetrahydrofolate or methotrexate. The preferred substrates for both binders appear to be the fully oxidized and partially reduced folates rather than the fully reduced folates. The lower-molecular-weight folate binding protein shows reversible binding with partially and fully reduced folates but irreversible binding with oxidized folates. This property suggests that this binder may have some function in the transport and storage of folate. The higher-molecular-weight folate binding protein, however, has only slight reversibility of binding with the partially and fully reduced folates, and it is therefore more difficult to postulate a physiologic function for this binding factor.
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PMID:The heterogeneity and properties of folate binding proteins from chronic myelogenous leukemia cells. 110 96