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Purification and characterization of strongly chitin‐binding chitinases from salicylic acid‐treated leek ( Allium porrum )
Author(s) -
Vergauwen Rudy,
Van Leuven Fred,
Van Laere André
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1040205.x
Subject(s) - tetramer , chitin , chitinase , isoelectric point , lysozyme , biochemistry , salicylic acid , molecular mass , agarose , isozyme , lectin , biology , enzyme , chemistry , chromatography , chitosan
Six chitinases (EC 3.2.1.14) were purified from salicylate‐treated leek ( Allium porrum L.). They all strongly bind to chitin and can roughly be divided into two groups. One group has blocked N‐termini, is completely inhibited by 1 m M AgNO 3 , has a relatively narrow pH optimum, a temperature optimum of 40°C and cannot degrade the tetramer of chitin. The other group has unblocked N‐termini showing homology to the chitin‐binding lectin WGA and is therefore considered as class I chitinases. This group is only moderately inhibited by 1 m M AgNO 3 (30%), has a relatively broad pH optimum, has a higher temperature optimum (50 to 60°C) and can degrade the tetramer of chitin to dimers. Furthermore, all isoforms have molecular masses around 34 kDa as estimated by SDS‐PAGE. They have isoelectric points ranging from 4 to 8 and no detectable lysozyme activity. Two isoforms investigated in more detail differ in their antifungal potential.