title: Enzymatic properties of endo-beta-N-acetylglucosaminidases from developing tomato fruits and soybean seeds: substrate specificity of plant origin endoglycosidase.
abstract: Substrate specificity and some other enzymatic properties of partial purified endo-beta-N-acetylglucosaminidases (endo-beta-GlcNAc-ase) from developing soybean seeds (Glycine max, Endo-GM) and developing tomato fruits (Lycopersicum esculentum, Endo-LE) were studied. The substrate specificity of these two endoglycosidases was explored and compared with regard to various pyridylaminated N-glycans derived from some naturally occurring glycoproteins. For Endo-GM and Endo-LE, several high mannose-type sugar chains bearing alpha 1-2 mannosyl residue(s), Man9-6GlcNAc2-PA (PA is pyridylamino) (80-100% relative hydrolysis), were most favored substrates followed by Man5GlcNAc2-PA (32% for Endo-LE, 43% for Endo-GM), a typical hybrid-type structure (GlcNAc1Man5GlcNAc2-PA; 34% for Endo-LE, 37% for Endo-GM), and then the common core pentasaccharide of N-glycan (Man3GlcNAc2-PA; 9% for Endo-GM and 16% for Endo-LE). On the contrary, both Endo-GM and Endo-LE could barely hydrolyze the xylose-containing N-glycans (Man3Xyl1GlcNAc2-PA, Man3Fuc1Xyl1GlcNAc2-PA) found ubiquitously in plant cells. The molecular mass of these two endoglycosidases was approximately 62 kDa by gel filtration and both Endo-GM and Endo-LE showed maximal activities for Man6GlcNAc2-PA in a weak acidic region (pH 6.0-6.5).
authors.affiliation: Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Tokuda
authors.forename: A
authors.initials: A
authors.lastname: Ohno
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Ishiguro
mesh_terms: D006863:Hydrogen-Ion Concentration; D018551:Solanum lycopersicum / Q000201:enzymology*; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000302:isolation & purification / Q000378:metabolism*; D012639:Seeds / Q000201:enzymology; D013025:Glycine max / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase