Specific xyloglucanases as a new class of polysaccharide-degrading enzymes.

摘要: Three specific xyloglucanases (XGs) were isolated from Aspergillus japonicus (32 kDa, pI 2.8), Chrysosporium lucknowense (78 3.8) and Trichoderma reesei (75-105 4.1-4.3). The characteristic feature of these enzymes was their high activity toward tamarind xyloglucan, whereas the against carboxymethylcellulose (CMC) barley beta-glucan absent or very low. Peptide mass fingerprinting using MALDI-TOF spectrometry showed that T. XG represents Cel74A, whose gene has been discovered recently (GenBank accession no. AY281371 ), but enzyme not characterized described elsewhere. Tryptic peptides A. C. did show any identity to those known glycoside hydrolases. All produced XXXG, XXLG/XLXG XLLG oligosaccharides as end products xyloglucan hydrolysis. displayed an endo-type attack on polymeric substrate, while mode action two other similar exo-type, when containing four glucose residues in main chain split off ends molecules. These results together with growing literature data allow concluding may represent a new class hydrolases, which are different regular endo-1,4-beta-glucanases.