Biomaterial Database

Uroporphyrinogen-I-synthetase activity in red blood cells of lead-exposed workers. 1982

A El-Waseef

Lead-exposed (n = 26) and control (n = 12) subjects were investigated for their blood lead concentration erythrocyte 5-amino-laevulinic acid dehydratase (5-ALAD) and erythrocyte uroporphyrinogen-I-synthetase (URO-I-S) activity; 5-amino-laevulinic acid (5-ALA) and porphobilinogen (PBG) were used as substrates in the synthetase assay. In the lead workers erythrocyte 5-ALA dehydratase was grossly inhibited but with PBG as substrate the synthetase activity was not significantly different from the control group. With 5-ALA as substrate the synthetase assay showed marked inhibition. Addition of zinc (0.1 mmol/l) and dithiotheritol (0.5 mmol/l) brought the activities of both the dehydratase and synthetase (using 5-ALA as substrate) back into the ranges seen in the control group. With porphobilinogen as substrate higher concentrations of zinc caused inhibition of the synthetase, whilst reduction of added zinc to 0.01 mmol/l resulted in stimulation of the synthetase. A good correlation (r = 0.87) was obtained in synthetase assay when PBG and 5-aminolaevulinate (with added zinc and dithiothreitol) were used as substrates. With these additions 5-ALA may be used as a substrate in the URO-I-S assay in the investigation of latent cases of acute intermittent porphyria.

UI	MeSH Term	Description	Entries
D007854	Lead	A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.2, symbol Pb.
D011162	Porphobilinogen
D011163	Hydroxymethylbilane Synthase	An enzyme that catalyzes the tetrapolymerization of the monopyrrole PORPHOBILINOGEN into the hydroxymethylbilane preuroporphyrinogen (UROPORPHYRINOGENS) in several discrete steps. It is the third enzyme in the 8-enzyme biosynthetic pathway of HEME. In humans, deficiency in this enzyme encoded by HMBS (or PBGD) gene results in a form of neurological porphyria (PORPHYRIA, ACUTE INTERMITTENT). This enzyme was formerly listed as EC 4.3.1.8	Porphobilinogen Ammonia-Lyase,Porphobilinogen Deaminase,Uroporphyrinogen I Synthase,Hydroxymethylbilane Synthetase,Pre-uroporphyrinogen Synthetase,Preuroporphyrinogen Synthetase,Ammonia-Lyase, Porphobilinogen,Deaminase, Porphobilinogen,Porphobilinogen Ammonia Lyase,Pre uroporphyrinogen Synthetase,Synthase, Hydroxymethylbilane,Synthase, Uroporphyrinogen I,Synthetase, Hydroxymethylbilane,Synthetase, Pre-uroporphyrinogen,Synthetase, Preuroporphyrinogen
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D004781	Environmental Exposure	The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.	Exposure, Environmental,Environmental Exposures,Exposures, Environmental
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000622	Aminolevulinic Acid	A compound produced from succinyl-CoA and GLYCINE as an intermediate in heme synthesis. It is used as a PHOTOCHEMOTHERAPY for actinic KERATOSIS.	5-Amino Levulinic Acid,5-Aminolaevulinate,5-Aminolevulinate,Aminolevulinic Acid Hydrochloride,Delta-Aminolevulinic Acid,Levulan,5 Amino Levulinic Acid,5 Aminolaevulinate,5 Aminolevulinate,Acid Hydrochloride, Aminolevulinic,Acid, 5-Amino Levulinic,Acid, Aminolevulinic,Acid, Delta-Aminolevulinic,Delta Aminolevulinic Acid,Hydrochloride, Aminolevulinic Acid,Levulinic Acid, 5-Amino
D000623	Porphobilinogen Synthase	An enzyme that catalyzes the formation of porphobilinogen from two molecules of 5-aminolevulinic acid. EC 4.2.1.24.	Aminolevulinate Hydro-Lyase,Aminolevulinic Acid Dehydratase,ALA-Dehydrase,delta-Aminolevulinate Dehydratase,delta-Aminolevulinic Acid Dehydratase,ALA Dehydrase,Acid Dehydratase, Aminolevulinic,Acid Dehydratase, delta-Aminolevulinic,Aminolevulinate Hydro Lyase,Dehydratase, Aminolevulinic Acid,Dehydratase, delta-Aminolevulinate,Dehydratase, delta-Aminolevulinic Acid,Hydro-Lyase, Aminolevulinate,Synthase, Porphobilinogen,delta Aminolevulinate Dehydratase,delta Aminolevulinic Acid Dehydratase