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A note on suxamethonium sensitivity and serum cholinesterase variants
Human Genetics
|April 15, 1976
Summary
Researchers re-examined serum cholinesterase in patients with prolonged apnoea. New variants sensitive only to succinylcholine (suxamethonium) were identified, suggesting novel atypical enzyme activity.
Area of Science:
- Biochemistry
- Pharmacogenetics
- Clinical Chemistry
Background:
- Prolonged apnoea can be associated with variations in serum cholinesterase activity.
- Standard phenotyping using dibucaine and fluoride inhibition may not detect all enzyme variants.
Purpose of the Study:
- To investigate serum cholinesterase variants in patients with prolonged apnoea who initially showed a normal phenotype (UU).
- To identify novel enzyme variants by using succinylcholine as a substrate.
Main Methods:
- Sera from 21 patients with prolonged apnoea and normal phenotype were re-analyzed.
- Succinylcholine was used as a substrate instead of benzoylcholine.
- Dibucaine number (DN) was determined for enzyme characterization.
Main Results:
- Nine samples exhibited normal enzyme activity but a low dibucaine number (DN < 20), indicating an atypical variant.
- Six sera showed no detectable enzyme activity.
- The remaining six samples had enzyme activity and DN comparable to healthy controls.
Conclusions:
- The study suggests the occurrence of new serum cholinesterase variants.
- These variants appear to be sensitive specifically to succinylcholine (suxamethonium).
- This finding highlights the importance of substrate variability in identifying pseudocholinesterase deficiencies.