Purification and characterization of strongly chitin‐binding chitinases from salicylic acid‐treated leek (Allium porrum) |
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Authors: | Rudy Vergauwen Fred Van Leuven André Van Laere |
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Institution: | R. Vergauwen and A. Van Laere (corresponding author, e‐mail;), Dept of Biology, Botany Inst., K. U. Leuven, Kardinaal Mercierlaan 92, B‐3001 Heverlee, Belgium;F. Van Leuven, K. U. Leuven, Dept of Human Genetics, Campus Gasthuisberg, Herestraat 49, B‐3001 Heverlee, Belgium. |
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Abstract: | 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 AgNO3, 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 AgNO3 (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. |
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Keywords: | Allium porrum antifungal leek strongly chitin‐binding chitinases (class I chitinases) |
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