Walraevens V, Vandermeers-Piret M C, Vandermeers A, Gourlet P, Robberecht P
Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
Biol Chem. 1999 Apr;380(4):485-8. doi: 10.1515/BC.1999.062.
The dried latex of the mountain papaya, Carica candamarcensis, was chromatographed on CM-Sephadex C50, giving rise to three peaks (CCI, CCII and CCIII) with amidase activity on N-alpha-benzoyl-DL-arginine-4-nitroanilide. The less basic, most active, peak, CCI, was separated into two components, CCIa and CCIb, by reverse-phase HPLC under denaturing conditions. The primary structures of CCIa and CCIb are presented. They were deduced from sequence analysis of the whole proteins and peptides resulting from enzymatic digestions. Both proteinases are made of 213 amino acid residues, CCIb sharing 88-89% similarity with the three subvariants (G90/R212, E90/R212, E90/K212) of CCIa. 139-140 amino acid residues (65.8%) of CCIa and 141 residues (66.5%) of CCIb are common to papain. The seven cysteine residues are aligned with those of papain and the catalytic triad (Cys25, His159, Asn175) of all cysteine peptidases of the papain family is conserved. The similarity with the other cysteine proteases from Carica papaya is discussed.
山地番木瓜（Carica candamarcensis）的干燥乳胶在CM-葡聚糖凝胶C50上进行色谱分析，产生了三个在N-α-苯甲酰-DL-精氨酸-4-硝基苯胺上具有酰胺酶活性的峰（CCI、CCII和CCIII）。碱性较弱、活性最高的峰CCI在变性条件下通过反相高效液相色谱法分离为两个组分，CCIa和CCIb。文中给出了CCIa和CCIb的一级结构。它们是通过对完整蛋白质和酶解产生的肽段进行序列分析推导出来的。两种蛋白酶均由213个氨基酸残基组成，CCIb与CCIa的三个亚变体（G90/R212、E90/R212、E90/K212）具有88 - 89%的相似性。CCIa的139 - 140个氨基酸残基（65.8%）和CCIb的141个残基（66.5%）与木瓜蛋白酶相同。七个半胱氨酸残基与木瓜蛋白酶的半胱氨酸残基排列一致，木瓜蛋白酶家族所有半胱氨酸肽酶的催化三联体（Cys25、His159、Asn175）保守。文中还讨论了与番木瓜（Carica papaya）其他半胱氨酸蛋白酶的相似性。
