HUMAN NONSECRETORY RIBONUCLEASES .2. STRUCTURAL CHARACTERIZATION OF THE N-GLYCANS OF THE KIDNEY, LIVER AND SPLEEN ENZYMES BY NMR-SPECTROSCOPY AND ELECTROSPRAY MASS-SPECTROMETRY
Cw. Lawrence et al., HUMAN NONSECRETORY RIBONUCLEASES .2. STRUCTURAL CHARACTERIZATION OF THE N-GLYCANS OF THE KIDNEY, LIVER AND SPLEEN ENZYMES BY NMR-SPECTROSCOPY AND ELECTROSPRAY MASS-SPECTROMETRY, Glycobiology, 3(3), 1993, pp. 249-259
The N-glycans have been removed by peptide-N-glycosidase F (PNGase F)
from purified human non-secretory RNases derived from kidney, liver an
d spleen. The spleen RNase was purified by two procedures, one of whic
h did not include the usual acid treatment step (0.25 M H2SO4, 45 min,
4-degrees-C), to determine if acid treatment alters the carbohydrate
moieties. The N-glycans of the RNases were fractionated by Bio-Gel P4
chromatography and analysed by 600 MHz H-1-NMR spectroscopy and electr
ospray mass spectrometry. All four non-secretory RNase preparations co
ntained the following structures: [GRAPHICS] The relative amounts of t
he trisaccharide, pentasaccharide and hexasaccharide appeared to vary
slightly in the different tissue RNases. The overall results indicate:
(i) that acid treatment during purification does not alter the N-glyc
ans of non-secretory RNases; (ii) that the N-glycans from kidney, live
r and spleen non-secretory RNases are very similar, if not identical,
to one another, but different from the N-glycan structures reported fo
r secretory RNase.