Biochemical characterisation of MX-4, a plant cysteine protease of broad specificity and high stability

详细信息    查看全文

• 作者：Mar&#xed ; a del Carmen Oliver-Salvador^a ; ^{oliveripn@hotmail.com} ; Zhirui Lian^b ; Richard A. Laursen^b ; V&#xed ; ctor M. Bolañ ; os-Garc&#xed ; a^c ; Manuel Soriano-Garc&#xed ; a^d ; ^{soriano@servidor.unam.mx}
• 关键词：Plant cysteine protease ; Pileus mexicanus ; Jacaratia mexicana ; Broad protease specificity ; Plant endopeptidase ; New analytical proteomics tool ; Cysteine protease of industrial interest
• 刊名：Food Chemistry
• 出版年：2011
• 出版时间：15 May 2011
• 年：2011
• 卷：126
• 期：2
• 页码：543-552
• 全文大小：1367 K

文摘

A new proteinase, mexicain-IV (MX-4), has been purified to homogeneity from the latex fruits of Jacaratia mexicana (formely Pileus mexicanus), a plant member of the Caricaceae family. MX-4 shows a Mr of 23.7 kDa, pI of 9.3 and maximum proteolytic activity on casein and BAPNA at pH 8.0–8.5 and pH 7.0–7.5, respectively. The amino acid sequence of MX-4 and its reversible inhibition by HgCl₂ show that the proteinase belongs to the family of cysteine proteinases. This enzyme exhibits rather broad substrate specificity, although there seems to be a slight preference for cleavage of peptides having certain hydrophobic residues in the P2 position. Biochemical and circular dichroism studies revealed that this enzyme belongs to the α + β class of proteins, in agreement with the results obtained by X-ray crystallographic structure determination, and showed that MX-4 has a higher pH and thermal stability than other members of the Caricaceae family, including papain. These properties make this novel protease a suitable novel analytical tool for the proteomic analysis of peptide fragments of great potential interest in the food industry and other industries.