Identification and Functional Characterization of Cysteine Protease from Nine Pear Cultivars (Pyrus pyrifolia)

Abstract

This study was performed to compare the total protein and protease content among the whole fruit, flesh, and peel of nine different pear cultivars. Pear proteases were functionally characterized with respect to three enzyme assays. Proteases from pears were further identified by sodium dodecyl sulfatepolyacrylamide gel electrophoresis, in gel activity staining, and matrix assisted laser desorption/ionization-time of flight mass spectrometry analysis. Flesh from Whasan, Nikita, and Hanareum cultivars contained relatively more total protein and protease and showed high enzyme activities, while Chuwhang contained the lowest amount of protein and protease activity. Protease content and enzyme activities found in the pear flesh or whole fruits were two to six times higher than those in the pear peel. Pear cultivars contained one or two protease bands with molecular weights of 36 kDa and/or 38k Da. The larger band was further identified as a cysteine proteinase with 70% homology to the pear cysteine protease from Pyrus pyrifolia.

Application of Plant Proteases in Meat Tenderization: Recent Trends and Future Prospects

“…However, its broad specificity also causes a mushy texture if the enzymatic action is not properly controlled. Pear fruit cysteine protease has been proposed as a potential alternative to bromelain to overcome the problem of a mushy texture [ 69 ]. The pH of meat and other processing parameters significantly affected the bromelain’s tenderizing efficiency.…”

Functional characterization of purified pear protease and its proteolytic activities with casein and myofibrillar proteins

“…Protease extraction from pear, fig, or kiwifruit Cysteine proteases from pear, fig, and kiwifruit powder were extracted with extraction buffer (10 mM cysteine, 1 mM EDTA, 50 mM sodium phosphate, pH 6.5) followed by a 60% ethanol precipitation as described previously (14,16). Here, cysteine in the extraction buffer is important to keep the activity of cysteine proteases because these proteases use a catalytic cysteine residue as a nucleophile during proteolysis and are activated by thiol compounds (20).…”

“…Pear proteases were identified by SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis), in-gel activity staining, and MALDI-TOF MS (matrix assisted laser desorption/ ionization-time of flight mass spectrometry) analysis and further characterized for their proteolytic activities with three different substrates (14). Also, optimum purification method of pear protease was studied by comparison of ethanol precipitation, two phases partitioning, or ion exchange chromatography (DEAE Sepharose alone or followed by Mono Q).…”

“…Dried samples were then further ground by a pulverizer (FM-681C; Hanil Electric Co., Ltd., Seoul, Korea) and stored at −20 o C in polyethylene bags. Proteolytic enzyme from pear, fig, or kiwifruit was extracted as described previously with slight modifications (14,16). Each powder (10 g) was mixed with extraction buffer (1 mM cysteine, 1 mM EDTA, 50 mM sodium phosphate, pH 6.5) at a ratio of 1:9 (w/v) and then incubated with gentle shaking at 4 o C for 1 h. The extract was centrifuged at 4 o C for 30 min at 15,000xg to remove insoluble materials (Avan-Tr J-E; Beckman Coulter, Brea, CA, USA).…”

Efficiency of selected food ingredients on protein efficiency ratio, glycemic index and in vitro digestive properties

“…Some medicinal herbs contain phytochemicals characterized by bitter and pungent properties exert their digestive action through endocrine and paracrine release (Valussi 2012). Few fruits such as pineapple, papaya, fig, and kiwi contain proteolytic enzymes such as bromelain, papain, ficin, and actinidin, respectively have been reported with digestive property (Nam et al 2016). Protease enzymes are known to break down or change the composition of proteins/peptides and helps in digestion process.…”