Glycoprotein synthesis in plants. I. Role of lipid intermediates

Journal Article · Tue Mar 01 04:00:00 EST 1977 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.59.3.341· OSTI ID:7306930

Ericson, M C; Delmer, D P

The enzymic processes involved in glycoprotein synthesis have been studied using crude extracts obtained from developing cotyledons of Phaseolus vulgaris harvested at the time of active deposition of vicilin. Radioactivity from GDP-(/sup 14/C)mannose can be incorporated by crude extracts into a single chloroform-methanol-soluble product as well as into insoluble product(s). Mannose is the sole /sup 14/C-labeled constituent of the lipid. The kinetics of incorporation of /sup 14/C, as determined by pulse and pulse-chase experiments using GDP-(/sup 14/C)mannose, as well as direct incorporation from added (/sup 14/C)mannolipid, shows that the mannolipid is an intermediate in the synthesis of the insoluble product(s). The characteristics of the mannolipid are consistent with it being a mannosyl phosphoryl polyprenol. The mannose is apparently attached to the lipid via a monophosphate linkage. Of the radioactivity in the insoluble product(s), about 20 percent is pronase-digestible during a ''pulse experiment.'' After a chase with unlabeled GDP-mannose, about 40 percent is pronase-digestible; the other 60 percent is as yet uncharacterized. A radioactive product soluble in a mixture of chloroform-methanol-H/sub 2/O can be extracted from the insoluble residue obtained during a pulse, but is no longer present after a chase. This product may be a lipid oligosaccharide, the final intermediate in glycoprotein synthesis. Data are presented on incorporation from UDP-N-(/sup 14/C)acetylglucosamine into both chloroform-methanol-soluble and -insoluble product(s). The results are consistent with an involvement of lipid intermediates in the glycosylation of protein in this system, and support the concept that the mechanisms of glycoprotein synthesis in higher plants are similar to those which have been reported for mammalian systems.

• Research Organization: Michigan State Univ., East Lansing
• OSTI ID: 7306930
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 59:3; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOMASS
BIOSYNTHESIS
CARBOHYDRATES
CARBON 14
CARBON ISOTOPES
CATALYSIS
ENERGY SOURCES
ENZYMES
EVEN-EVEN NUCLEI
GLUCOPROTEINS
HEXOSES
ISOTOPES
KINETICS
LABELLING
LIGHT NUCLEI
LIPIDS
MAMMALS
MANNOSE
METABOLISM
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
PLANTS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RENEWABLE ENERGY SOURCES
SACCHARIDES
SYNTHESIS
VERTEBRATES
YEARS LIVING RADIOISOTOPES