Relationships between distribution of lead in erythrocytes in vivo and in vitro and inhibition of ALA-D.
Proteins in the ALA-D (delta-aminolaevulinic acid dehydratase) fraction from gel filtration of erythrocyte supernatant (ES) have the highest affinity for lead among erythrocyte constituents in vivo and in vitro. It takes 20-40 hours for erythrocyte components to be equilibrated with lead added in vitro. AT low lead concentrations, under 60 micrograms/100 ml ES, the extent of decrease in ALA-D activity indicates the extent of lead saturation of ALA-D fraction proteins. The saturation is attained at 80-110 micrograms/100 ml ES. Although an appreciable amount of lead is also found in the haemoglobin fraction that contains certain factors concerned in ALA-D inhibition, lead responsible for inducing the inhibition is not bound to haemoglobin fraction proteins but to ALA-D fraction proteins. Of three treatments or agents recovering the enzyme from lead effects, zinc is the only one that can fully restore the inhibition.
D002850:Chromatography, Gel; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D007854:Lead / Q000097:blood*; D009787:Occupational Medicine; D000623:Porphobilinogen Synthase / Q000037:antagonists & inhibitors* / Q000097:blood; D011485:Protein Binding; D014018:Tissue Distribution
D007854:Lead; D000623:Porphobilinogen Synthase