ENZYMATIC-PROPERTIES OF ENDO-BETA-N-ACETYLGLUCOSAMINIDASES FROM DEVELOPING TOMATO FRUITS AND SOYBEAN SEEDS - SUBSTRATE-SPECIFICITY OF PLANT-ORIGIN ENDOGLYCOSIDASE
Y. Kimura et al., ENZYMATIC-PROPERTIES OF ENDO-BETA-N-ACETYLGLUCOSAMINIDASES FROM DEVELOPING TOMATO FRUITS AND SOYBEAN SEEDS - SUBSTRATE-SPECIFICITY OF PLANT-ORIGIN ENDOGLYCOSIDASE, Biochimica et biophysica acta (G). General subjects, 1381(1), 1998, pp. 27-36
Substrate specificity and some other enzymatic properties of partial p
urified 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 w
ith regard to various pyridylaminated N-glycans derived from some natu
rally occurring glycoproteins. For Endo-GM and Endo-LE, several high m
annose-type sugar chains bearing alpha 1-2 mannosyl residue(s), Man(9-
6)GlcNAc(2)-PA (PA is pyridylamino) (80-100% relative hydrolysis), wer
e most favored substrates followed by Man(5)GlcNAc(2)-PA (32% for Endo
-LE, 43% for Endo-GM), a typical hybrid-type structure (GlcNAc(1)Man(5
)GlcNAc(2)-PA; 34% for Endo-LE, 37% for Endo-GM), and then the common
core pentasaccharide of N-glycan (Man(3)GlcNAc(2)-PA; 9% for Endo-GM a
nd 16% for Endo-LE). On the contrary, both Endo-GM and Endo-LE could b
ar:ly hydrolyze the xylose-containing N-glycans (Man(3)Xyl(1)GlcNAc(2)
-PA, Man(3)Fuc(1)Xyl(1)GlcNAc(2)-PA) found ubiquitously in plant cells
. The molecular mass of these two endoglycosidases was approximately 6
2 kDa by gel filtration and both Endo-GM and Endo-LE showed maximal ac
tivities for Man(6)GlcNAc(2)-PA in a weak acidic region (pH 6.0-6.5).
(C) 1998 Elsevier Science B.V. All rights reserved.