title: The heme biosynthetic pathway in lymphocytes of patients with malignant lymphoproliferative disorders.
abstract: The metabolism of heme is impaired in lymphocytes of patients with malignant lymphoproliferative disorders (MLPO). Two of the enzymes of the heme biosynthetic pathway, delta-aminolevulinic acid dehydrase (ALAD) (EC 4.2.1.24) and ferrochelatase (FC) (EC 4.99.1.1) are markedly reduced. The activity of porphobilinogen deaminase (PBGD) (EC 4.3.1.8) is increased. The rate-limiting enzyme of heme biosynthesis in the liver, aminolevulinate synthase (ALAS) (EC 2.3.1.37) remains unchanged although the concentration of total heme in the lymphocytes is markedly reduced. This might reflect a lack of negative feedback inhibition by heme on ALAS activity in this system.
authors.affiliation: Laboratory of Biochemical Pharmacology, Beilinson Medical Center, Petah Tiqva, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Schoenfeld
authors.forename: O
authors.initials: O
authors.lastname: Epstein
authors.forename: M
authors.initials: M
authors.lastname: Lahav
authors.forename: R
authors.initials: R
authors.lastname: Mamet
authors.forename: M
authors.initials: M
authors.lastname: Shaklai
authors.forename: A
authors.initials: A
authors.lastname: Atsmon
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000097:blood; D005294:Ferrochelatase / Q000097:blood; D006418:Heme / Q000096:biosynthesis*; D006801:Humans; D011163:Hydroxymethylbilane Synthase / Q000097:blood; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D008232:Lymphoproliferative Disorders / Q000097:blood*; D000623:Porphobilinogen Synthase / Q000097:blood
chemical_list: D006418:Heme; D000624:5-Aminolevulinate Synthetase; D011163:Hydroxymethylbilane Synthase; D000623:Porphobilinogen Synthase; D005294:Ferrochelatase