Processing pathway deduced from the structures of N-glycans in Carica papaya.
A processing The processing pathway of N-glycans in Carica papaya was deduced from the structures of N-glycans. The N-glycans were liberated by hydrazinolysis followed by N-acetylation. Their reducing-end sugar residues were tagged with 2-aminopyridine and the pyridylamino (PA-) sugar chains thus obtained were purified by HPLC. Eleven PA-sugar chains were found, and their structures were analyzed by two-dimensional sugar mapping combined with partial acid hydrolysis and exoglycosidase digestion. The structures of the N-glycans were of the highmannose types with xylose and fucose; however, among them two new N-glycans, Manalpha1-6(Manalpha1-3)Manalpha1-6(Xylbeta1-2)+ ++Manbeta1-4GlcNAcbeta1- 4(Fucalpha1-3)GlcNAc and Manalpha1-3Manalpha1-6(Xylbeta1-2)Manbeta1-4G lcNAcbeta1-4(Fucalpha1-3 )GlcNAc, were found. Judging from these structures together with Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) (Xylbeta1-2)Manbeta1- 4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc reported previously [Shimazaki, A., Makino, Y., Omichi, K., Odani, S., and Hase, S. (1999) J. Biochem. 125, 560- 565], a processing pathway for N-glycans in C. papaya is inferred in which the activity of Golgi alpha-mannosidase II is incomplete.
Makino
Y
Y
Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
Shimazaki
A
A
Omichi
K
K
Odani
S
S
Hase
S
S
D000631:Aminopyridines / Q000737:chemistry; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D005643:Fucose / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry; D007840:Latex / Q000737:chemistry / Q000378:metabolism; D019684:Magnoliopsida / Q000737:chemistry / Q000378:metabolism; D008358:Mannose / Q000737:chemistry*; D008361:Mannosidases / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011509:Proteoglycans / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014994:Xylose / Q000737:chemistry
D000631:Aminopyridines; D007840:Latex; D011509:Proteoglycans; D005643:Fucose; D014994:Xylose; D006026:Glycoside Hydrolases; D008361:Mannosidases; C038829:mannosyl-oligosaccharide 1,3 - 1,6-alpha-mannosidase; D008358:Mannose