Plasma and blood lead in humans : Capacity-limited binding to delta-aminolevulinic acid dehydratase and other lead-binding components.
In 42 lead-exposed workers (22 male and 20 female), we found a close nonlinear relation between blood and plasma lead concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS).
The concentration medians and ranges were lead in whole blood, 270 (97 to 950) mug/L and lead in plasma, 1.1 (0.2 to 13) mug/L. Proteins from lysed erythrocytes were studied by gel chromatography with ICP-MS detection.
We then found capacity-limited binding for lead to delta-aminolevulinic acid dehydratase (ALAD), as well as to two other components (with apparent molecular masses of 45 and<10 kDa, respectively).
The strongest affinity for lead was indicated for ALAD (35-81% of the lead in blood) and could be described by a capacity of 850 mug/L and a dissociation constant of 1.5 mug/L. The 45-kDa protein carried 12-26% of the blood lead, and the<10-kDa component less than 1%. A model based on these three components, plus a fourth one for unrecovered lead (2-45%), is proposed.
No binding of lead to hemoglobin was found.
There was an association between zinc and lead in whole blood ; however, zinc did not significantly affect the lead distribution in erythrocytes. 1998 Society of Toxicology.
Mots-clés Pascal : Toxicité, Polluant, Métal lourd, Plomb, Homme, Exposition professionnelle, Médecine travail, Analyse quantitative, Liquide biologique, Sang, Plasma sanguin, Spectrométrie masse, Spectrométrie ICP, Fixation biologique, Porphobilinogen synthase, Hydro-lyases, Carbon-oxygen lyases, Lyases, Enzyme
Mots-clés Pascal anglais : Toxicity, Pollutant, Heavy metal, Lead, Human, Occupational exposure, Occupational medicine, Quantitative analysis, Biological fluid, Blood, Blood plasma, Mass spectrometry, Inductive coupling plasma spectrometry, Biological fixation, Porphobilinogen synthase, Hydro-lyases, Carbon-oxygen lyases, Lyases, Enzyme
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0184763
Code Inist : 002B03L05. Création : 16/11/1999.