Bromhexine and its inhibitory effect on lipase - kinetics and structural study.

Lipase hydrolyses the ester bonds in triglyceride. It is an important enzyme in medicine and industry. Some pathogen bacteria use this exoenzyme to disrupt the extracellular matrix of host organisms. Pseudomonas uses various extracellular enzymes such as lipase to invade its host. In this report, for the first time, bromhexine was introduced as an inhibitor of lipase. Bromhexine is a mucolytic drug which is used in the treatment of respiratory tract disorders. The results showed that bromhexine inhibited the enzyme by competitive inhibition. IC50 and Ki values of the drug were 0.049 mM and 0.02 mM, respectively. Arrhenius plot showed that the drug reduced the activation energy. The enzyme was purified and SDS-PAGE showed that its molecular weight is 13 kDa. Fluorescence measurement revealed that binding of the drug to lipase could make structural changes in the enzyme. Inhibition of lipase by bromhexine could be applicable in medicine.