Arabinogalactan Protein from a Crude Cell Organelle Fraction of Phaseolus vulgaris L.
Sonication of a crude cell organelle fraction from hypocotyl tissue of dark-grown bean seedlings, and from suspension-cultured cells released a hydroxyproline-containing protein. The purification of this protein is described. It was found to be an arabinogalactan protein composed of 90% carbohydrate and 10% protein. The major sugars are galactose, arabinose, and uronic acids, and the major amino acids are hydroxyproline, serine, and alanine. Its molecular weight was estimated at 1.4 x 10(5) daltons and the isoelectric point at pH 2.3. The molecule is soluble in 5% trichloroacetic acid and can be precipitated with beta-galactosyl Yariv antigen. Pulse-chase experiments indicated that it was a secretory protein. The biosynthesis of arabinogalactan proteins is discussed.
van Holst
G J
GJ
Plantenfysiologisch Laboratorium, Universiteit van Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.
Klis
F M
FM
de Wildt
P J
PJ
Hazenberg
C A
CA
Buijs
J
J
Stegwee
D
D