Macromolecular components of tomato fruit pectin.
Chelate and alkaline-soluble pectin extracted from cell walls of pericarp tissue from mature green, turning, and red ripe (Lycopersicon esculentum Mill.) fruit (cv. Rutgers), were studied by high-performance size-exclusion chromatography. Computer-aided curve fitting of the chromatograms to a series of Gaussian-shaped components revealed that pectin from all fractions was composed of a linear combination of five macromolecular-sized species. The relative sizes of these macromolecules as obtained from their radii of gyration were 1:2:4:8:16. Dialysis against 0.05 M NaCl induced partial dissociation of the biopolymers. Apparently, the weight fraction of smaller sized species increased at the expense of larger ones. Also, the dissociation produced low-molecular-weight fragments. Behavior in the presence of 0.05 M NaCl led to the conclusion that cell wall pectin acted as if it were an aggregated mosaic, held together at least partially through noncovalent interactions.
U.S. Department of Agriculture, ARS, Eastern Regional Research Center, Philadelphia, Pennsylvania 19118.
M L
ML
Fishman
K C
KC
Gross
D T
DT
Gillespie
S M
SM
Sondey
D002473:Cell Wall / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003956:Dialysis; D008970:Molecular Weight; D010368:Pectins / Q000032:analysis*; D010940:Plant Proteins / Q000302:isolation & purification; D010944:Plants / Q000032:analysis*
D010940:Plant Proteins; D010368:Pectins