title: Partial properties of an aspartic protease in bitter gourd (Momordica charantia L.) fruit and its activation by heating.
abstract: Bitter gourd (BG fruit) is usually heated in hot water to reduce bitterness and improve flavour before being served. Protein extract from BG was analyzed for protease activity by gelatin-gel electrophoresis. The study showed that the proteolytic activity in BG flesh was enhanced by heat-treatment at temperatures ranging from 50°C to 75°C. An aspartic protease (AP) was characterized by gel electrophoresis. The optimal AP activity was at pH 7; the pI of the AP was demonstrated to be 4.8; the protein molecular weight of the BG-AP was estimated to be 60KD by SDS-PAGE. The AP was implicated in the proteolysis of the photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase. The AP was further purified and submitted for analysis of peptide mass fingerprint (PMF). The Mascot peptide mass fingerprint of the AP protein hit no existing protein (score>60), and it proved to be a novel AP.
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 111, Qinghua Donglu No. 17, Beijing 100083, PR China.
authors.forename: Lianzhen
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 111, Qinghua Donglu No. 17, Beijing 100083, PR China.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 111, Qinghua Donglu No. 17, Beijing 100083, PR China.
authors.forename: Quanhong
authors.initials: Q
authors.lastname: Li
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 111, Qinghua Donglu No. 17, Beijing 100083, PR China.
authors.forename: Tongyi
authors.initials: T
authors.lastname: Cai
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, P.O. Box 111, Qinghua Donglu No. 17, Beijing 100083, PR China. Electronic address: jwb@cau.edu.cn.
authors.forename: Weibo
authors.initials: W
authors.lastname: Jiang
keywords: Activation; Aspartic protease; Bitter gourd; Heat-treatment; SDS–gelatin–PAGE