Abstract
A chymotrypsin inhibitor was isolated and purified from the seeds of Enterolobium saman (Leguminaceae family) by extraction with 100 mM phosphate buffer, heat treatment, ammonium sulphate precipitation, ion-exchange chromatography on DEAEcellulose and filtration through Sephadex G-75. The final preparation appeared to be homogeneous by both chromatographic and electrophoretic analyses. ESCI had a molecular weight of about 17,890 and an isoelectric point of 5.8. ESCI inhibited bovine chymotrypsin at an inhibitor-enzyme molar ratio of 1:2. The inhibition mode of chymotrypsin inhibitor was competitive on bovine chymotrypsin. Investigation has been carried out on the complex formed between chymotrypsin and chymotrypsin inhibitor by physico-chemical methods. An apparent dissociation constant (Ki) of 9.05 X 10-8 M has been calculated for the complex. This enzyme- inhibitor complex was isolated by gel filtration on Sephadex G-75 and a molecular weight of 43.000 was estimated for the complex. The inhibitor did not have any effect on other proteinases, such as papain, bromelin, elastase, α -amylase, trypsin and pepsin. The chemical modification of lysine residues indicated that –NH2 groups are not essential for the activity of ESCI toward chymotrypsin. The inhibitor was an acidic protein and was stable over a wide pH range of 2-12 and temperature range of 10o C-97o C.
Highlights
The protease inhibitor (PI) protein, the natural antagonists of protease, is a small protein which is quite common in nature and present in all life forms (Fritz, 2000)
The present paper describes the extraction, purification and biochemical characterization of chymotrypsin inhibitor from Enterolobium saman seeds
The supernatant was separated by centrifugation (30 min at 10.000 rpm) and the clear supernatant was used as a crude extract for estimation of chymotrypsin inhibitory activity and protein
Summary
The protease inhibitor (PI) protein, the natural antagonists of protease, is a small protein which is quite common in nature and present in all life forms (Fritz, 2000). The biological role of protein proteinase inhibitors is not still sufficiently clear, it has been suggested that they may perform three main functions-serving as storage proteins, being regulators of activity of endogenous proteinases and acting as agents protecting plants against insects and pathogenic microflora. These inhibitors are probably important physiologically and even in molecular evolution. They serve as excellent models for research on protein-protein interaction. The present paper describes the extraction, purification and biochemical characterization of chymotrypsin inhibitor from Enterolobium saman seeds
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Sultan Qaboos University Journal for Science [SQUJS]
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
