The Study of Inhibition of Lipase Activity in Pseudomonas aeroginosa

Lipases are one of the groups of enzymes which are important in medicine and industry. In gastrointestinal tract of human, lipase catalysis break down of triglyceride. Bacteria have also lipases which break down triglyceride in their culture medium and can use its fatty acids as carbon source. Dicyclomine is an antispasmodic drug that relieves smooth muscle spasm of the gastrointestinal tract. Few drugs have been determined to inhibit lipase activity, in this research; dicyclomine was introduced as an inhibitor of lipase, for the first time.
Lipase was extracted from Pseudomonas aeruginosa and the effect of dicyclomine was tested on its activity. The bacterium was cultured in medium with olive oil as carbon source and the supernatant was used for enzyme assay. For monitoring the enzyme activity, Para nitrophenyl palmitate (pNPP) was used as a substrate and the induced product was measured by visible spectrophotometer. Lineweaver-Burk plot was utilized for revealing the type of binding.
This research has shown that dicyclomine can inhibit lipase. Inhibition plot determined that the drug can inhibit the enzyme by competitive manner. Calculation of Ki and IC50 values showed that the drug can bind to the enzyme with high affinity. The study of enzyme activity in different pH and temperature revealed that optimum activity of enzyme, in the presence or absence of the drug, was observed in pH 8 and 60oC.
For the first time, dicyclomine was introduced as an inhibitor of lipase and the kinetics factors of the drug were investigated.