Protease inhibitors of pigeonpea (Cajanus cajan) and its wild relatives

Abstract

Plant protease inhibitors have been implicated in defense against insect pests. Podborer and pod fly are major pests of developing seeds of pigeonpea (Cajanus cajan L. Millsp.). Therefore, we studied the presence of protease inhibitors in seeds of pigeonpea and its wild relatives. Seed extracts were analyzed for protease inhibitor activities by caseinolytic assay, and the number of protease inhibitors determined by polyacrylamide gel electrophoresis. Besides trypsin and chymotrypsin inhibitors, seed extracts contained weak papain inhibitor(s) but no bromelain inhibitor. Treatment of seed extract with bromelain generated new active forms of trypsin inhibitors. The relative amounts of different trypsin inhibitors and the total trypsin inhibitor activity varied with different extraction media. Trypsin inhibitors were not detectable in pigeonpea leaves. The profiles of trypsin and chymotrypsin inhibitors in almost all the cultivars of pigeonpea analyzed were similar; however, those in wild relatives were quite variable.

Purification and characterization of a newly serine protease inhibitor from Rhamnus frangula with potential for use as therapeutic drug

“…1b, the highest protease inhibitor activity was recorded in the crude extract prepared in 0.1 M phosphate buffer (pH 7.6) (86 ± 5.1% inhibition) followed by the one prepared in distilled water (55 ± 6.1% inhibition). Similar results are reported for the maximal extraction of proteins from Moringa oleifera leaves (Bijina et al 2011) and Cajanus cajan seeds (Pichare and Kachole 1996). Thus, R. frangula leaves which may be a rich source of protease inhibitor were considered for further studies.…”

“…Homogenates were incubated in a rotary shaker at 200 rpm and at room temperature for 4 h, filtered and centrifuged at 12,000 rpm and 4°C for 15 min (Pichare and Kachole 1996). The protease inhibitor activity was then assayed in the resulting soluble crude extracts and the one that support the maximal activity was selected for further studies.…”

Inhibitors From Pigeonpea Active Against Lepidopteran Gut Proteinases

“…2 and 3). In contrast, the cultivars of pigeonpea showed variation in inhibitor isoforms when they were separated by isoelectric focusing and detected by agarose trypsin overlay method (Pichare and Kachole 1996). However, the same cultivars showed similar number of inhibitor isoforms when separated in gelatin-PAGE under nondenaturing condition and visualized by X-ray Þlm contact print method (Pichare and Kachole 1994).…”

Purification and Biochemical Characterization of a New Protease Inhibitor from Conyza dioscoridis with Antimicrobial, Antifungal and Cytotoxic Effects

“…Extracts prepared with 0.1 M phosphate buffer were much better than those prepared from the other tested solvents because the protease inhibitor activity was maximal (83% ± 3). In fact, several previous studies have shown that 0.1 M phosphate buffer (pH 7.6) allows a high amount of trypsin inhibitor activity from Cajanus cajan seeds [ 29 ]. After purification of the protease inhibitor, SDS-PAGE analysis of the obtained fractions clearly indicated that the protease inhibitor (named PDInhibitor) possesses a molecular mass of approximately 25 kDa, suggesting that the purified inhibitor protein belongs to the serine protease inhibitor family, characterized by a molecular mass ranging from 18 to 26 kDa [ 30 ].…”