A New Sugar Chain of the Proteinase Inhibitor from Latex of Carica papaya

Abstract

The structure of a sugar chain of the proteinase inhibitor from the latex of Carica papaya was studied. Sugar chains liberated on hydrazinolysis were N-acetylated, and their reducing-end residues were tagged with 2-aminopyridine. One major sugar chain was detected on size-fractionation and reversed-phase HPLC analyses. The structure of the PA-sugar chain was determined by two-dimensional sugar mapping combined with sequential exoglycosidase digestion and partial acid hydrolysis, and by 750 MHz 1H-NMR spectroscopy. The structure found was Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) (Xylbeta1-2)Manbeta1- 4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc. This sugar chain represents a new plant-type sugar chain with five mannose residues.

Crystal Structure of Papaya Glutaminyl Cyclase, an Archetype for Plant and Bacterial Glutaminyl Cyclases

“…Coordinates and stereochemical parameters of sugar moieties were downloaded from the Hetero-compound Information Center (HIC-UP, Uppsala, Sweden) 55 and the carbohydrate chains were built with the TURBO-FRODO molecular modelling program, 56 based on the work published about structures of N-glycans in C. papaya. 57,58 The progress of refinement and rebuilding was monitored with the free R-factor (R free ) computed from a randomly omitted 5% of the observed reflections. The refinement with CNS proceeded using automatically determined X-ray/ geometric (W a ) and X-ray/Brestraints (R weight ) weights and ended with values for R and R free of 20.8 and 24.1%, respectively.…”

N-Linked Glycan Structures of Human Lactoferrin Produced by Transgenic Rice

“…Shimazaki et al 26) reported that M2AFX elutes earlier than M2BFX in RP-HPLC. The PA-sugar chain contained in peak 3a showed the same retention time as M2AFX.…”

Cloning of a Zinc-binding Cysteine Proteinase Inhibitor in Citrus Vascular Tissue

“…This band may represent an additional member of this family present in citrus. Alternatively it might be a result of modifi cation of a portion of the CVZBP by glycosylation similar to three other members of the KSPI family (Odani et al, 1996;Shimazaki et al, 1999;Socorro et al, 2002;Takahashi et al, 1990).…”