Biomaterial Database

Interaction of divalent metal ions with normal and lead-inhibited human erythrocytic porphobilinogen synthase in vitro. 1987

J P Farant, and D C Wigfield

The effects of Zn2+, Hg2+, Cd2+, and Cu2+ on normal and lead-inhibited erythrocytic porphobilinogen synthase (PBG-S) were studied in vitro using human whole blood hemolysate. The results demonstrate that each of the divalent ions tested has a characteristic effect on the pH-activity relationship of PBG-S. The effects for a given ion are concentration- and pH-dependent. For Zn2+ these effects are also time-dependent. The results obtained provide an explanation for the contradictory reports of the action of some of the metals in vitro and indicate that future investigations of the effects of metals on an enzyme such as PBG-S are best performed over a judiciously selected pH range rather than at a single pH value. It is also shown that the metals studied will only have a significant effect on the proposed PBG-S activity ratio test for lead intoxication in instances of gross contamination of blood collection devices. The activation and/or inhibition of PBG-S and associate pH-activity profile changes resulting from interaction with the four metal ions tested were attributed to their respective affinity for the thiol and other groups at the active sites. The occurrence of a relatively specific pH optimum for PBG-S after interaction with each ion investigated remains unexplained.

UI	MeSH Term	Description	Entries
D007854	Lead	A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.2, symbol Pb.
D008628	Mercury	A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.
D008670	Metals	Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)	Metal
D002104	Cadmium	An element with atomic symbol Cd, atomic number 48, and atomic weight 112.41. It is a metal and ingestion will lead to CADMIUM POISONING.
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
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
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
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
D015032	Zinc	A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.