Monoclonal antibodies distinguish between carboxylesterase isoenzymes in different tissues of rat and guinea pig.
The carboxylesterase (CarbE) activity in the main tissues (lung, liver, plasma and small intestine) of both the rat and guinea pig was separated by chromatofocusing. The three CarbE isoenzymes in the small intestine from both species showed nearly identical pI values. Monoclonal antibodies (MAbs) raised against rat lung CarbE (pI 5.8) were used in enzyme-linked immunosorbent assays to distinguish between these closely related CarbE isoenzymes. None of the MAbs did bind to the active site as no inhibition of the enzyme was seen when the MAbs were added. The immunological study showed a strong relationship between lung CarbE (pI 5.8) and the rat liver CarbE (pI 6.0). The MAbs were also strongly bound to the high pI forms of the CarbE isoenzymes in plasma and small intestine from both rat and guinea pig, but not with the low pI forms. These results indicate that two immunochemically distinct categories of CarbE isoenzymes are present in the plasma and small intestine.
Gaustad
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Norwegian Defence Research Establishment, Division for Environmental Toxicology, Oslo.
Løvhaug
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D000818:Animals; D000911:Antibodies, Monoclonal; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay; D006168:Guinea Pigs; D007421:Intestine, Small / Q000201:enzymology; D007527:Isoenzymes / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D051381:Rats
D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D002265:Carboxylic Ester Hydrolases; D043182:Carboxylesterase