Related Experiment Videos
Human gastric lipase: a sulfhydryl enzyme
Y Gargouri1, H Moreau, G Pieroni
1Centre de Biochimie et de Biologie Moléculaire, Centre National de la Recherche Scientifique, Marseille, France.
The Journal of Biological Chemistry
|February 15, 1988
Summary
Human gastric lipase activity is dependent on a sulfhydryl group. Modification of this group with specific reagents leads to complete enzyme inactivation, confirming its role as a sulfhydryl enzyme.
Area of Science:
- Biochemistry
- Enzymology
Background:
- Human gastric lipase is a key enzyme in fat digestion.
- Understanding the enzyme's active site is crucial for its functional characterization.
Purpose of the Study:
- To investigate the role of sulfhydryl groups in human gastric lipase activity.
- To determine if human gastric lipase is a sulfhydryl enzyme.
Main Methods:
- Incubation of human gastric lipase with sulfhydryl-modifying reagents: 5,5'-dithiobis(2-nitrobenzoic acid), 4,4'-dithiopyridine, and dodecyldithio-5-(2-nitrobenzoic acid).
- Assay of residual enzyme activity after modification.
- Correlation of sulfhydryl group modification with enzyme activity loss.
Main Results:
- Modification of one sulfhydryl group per mole of enzyme correlated with loss of activity using 5,5'-dithiobis(2-nitrobenzoic acid) and 4,4'-dithiopyridine.
- Immediate and complete inactivation of human gastric lipase occurred with the hydrophobic reagent dodecyldithio-5-(2-nitrobenzoic acid) across a range of pH values.
- Dodecyldithio-5-(2-nitrobenzoic acid) rapidly inhibited tributyrin hydrolysis.
Conclusions:
- Human gastric lipase activity is critically dependent on a specific sulfhydryl group.
- The enzyme functions as a sulfhydryl enzyme, indicating the essentiality of this functional group for its catalytic activity.