Triticum aestivum L. endoxylanase inhibitor (TAXI) consists of two inhibitors, TAXI I and TAXI II, with different specificities.
The Triticum aestivum L. endoxylanase inhibitor (TAXI) discovered by Debyser and Delcour [(1997) Eur. Pat. filed April 1997, published as WO 98/49278] and Debyser, Derdelinckx and Delcour [(1997) J. Am. Soc. Brew. Chem. 55, 153-156] seems to be a mixture of two different endoxylanase inhibitors, called TAXI I and TAXI II. By using Aspergillus niger as well as Bacillus subtilis endoxylanases for assaying inhibition activity, both inhibitors could be purified to homogeneity from wheat (Triticum aestivum L., var. Soissons). TAXI I and TAXI II have similar molecular structures. They both have a molecular mass of approx. 40.0 kDa, are not glycosylated and occur in two molecular forms, i.e. a non-proteolytically processed one and a proteolytically processed one. However, the pI of TAXI II (at least 9.3) is higher than that of TAXI I (8.8). TAXI I and TAXI II clearly show different inhibition activities towards different endoxylanases. The N-terminal amino acid sequences of both inhibitors show a high degree of identity, which might indicate that there is an evolutionary relationship between them.
Gebruers
K
K
Laboratory of Food Chemistry, Katholieke Universiteit Leuven, Kardinaal Mercierlaan 92, B-3001 Heverlee, Belgium. kurt.gebruers@agr.kuleuven.ac.be
Debyser
W
W
Goesaert
H
H
Proost
P
P
Van Damme J
Delcour
J A
JA
D000595:Amino Acid Sequence; D002852:Chromatography, Ion Exchange; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D043364:Endo-1,4-beta Xylanases; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D007525:Isoelectric Focusing; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D014908:Triticum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D014995:Xylosidases / Q000037:antagonists & inhibitors*
D004791:Enzyme Inhibitors; D010940:Plant Proteins; C422246:TAXI I protein, Triticum aestivum; C422247:TAXI II protein, Triticum aestivum; D014995:Xylosidases; D043364:Endo-1,4-beta Xylanases