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

A mixture of two ionic forms of a folate-binding protein purified from chronic myelogenous leukemia cells reversibly binds N5,N10-methylene tetrahydrofolate and prevents the coupling of this cofactor to thymidylate synthetase in a terniary complex with fluorodeoxyuridylate. The binding protein also inhibits the enzymic synthesis of thymidine monophosphate by preventing the methylation of deoxyuridylate. These findings suggest that one function of the folate-binding protein may be to regulate the intracellular concentration of free folate cofactors and, thereby, modulate their functional activity.
 ...
PMID:Binding of N5,N10-methylene tetrahydrofolate and the inhibition of thymidylate synthesis by a folate-binding protein. 70 90

Folate-binding proteins were isolated from the particulate fraction (44,000 X g pellet) and the soluble fraction (44,000 X g supernate) of the homogenate of a spleen obtained from a patient who had an acute leukemic (blast) transformation of chronic myelogenous leukemia. The folate-binding activity which was obtained from the particulate fraction by solubilization with 1% Triton X-100 could be resolved into two binding proteins (Mr 310,000 and 28,000) by gel filtration through Sephadex G-200 after incubation with excess [3H]pteroylglutamic acid (PteGlu). The folate-binding protein in the solubilized particulate fraction and the soluble folate-binding protein in the 44,000 X g supernatant cytoplasm were purified by affinity chromatography. Only a 32 kDa protein was identified by SDS-polyacrylamide gel electrophoresis in the final preparation of the purified folate-binding protein from the particulate, whereas two protein bands (Mr 42,000 and 32,000) were identified by SDS-polyacrylamide gel electrophoresis in the purified preparation of the soluble folate-binding protein. Both of these species were immunologically crossreacting. Both the purified folate-binding protein from the particulate fraction and the purified soluble form had higher affinity for oxidized folate than for the reduced folate cofactors, and both proteins had very low affinity for the antifolate compound, methotrexate. The amino-acid composition of the soluble folate-binding protein was similar with regard to the content of apolar amino acids to that reported for the membrane-derived folate-binding protein purified from milk and human placenta.
 ...
PMID:Characterization of multiple forms of folate-binding protein from human leukemia cells. 346 Jun 37