Identification and characterization of a sucrose transporter isolated from the developing cotyledons of soybean

• Published in: Archives of biochemistry and biophysics Vol. 409; no. 2; pp. 243 - 250
• Main Authors: Aldape, Mike J, Elmer, Aaron M, Chao, Wun S, Grimes, Howard D
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-01-2003
• Subjects: Biological Transport; Carbon - metabolism; Cotyledon - genetics; Cotyledon - growth & development; Cotyledon - metabolism; Genome, Plant; Glycine max - genetics; Glycine max - growth & development; Glycine max - metabolism; Hydrogen-Ion Concentration; LAHC; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Transport Proteins - chemistry; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; MFS; Phylogeny; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Protein Structure, Tertiary; Saccharomyces cerevisiae - genetics; Soybean; Sucrose; Sucrose - metabolism; Sucrose - pharmacokinetics; Sucrose transport; Sucrose transporter; SUT; SUT; LAHC; Sucrose; Carbon metabolism; Sucrose transport; Sucrose transporter; Soybean; MFS
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/S0003-9861(02)00631-8

Reduced carbon produced in mature leaves is distributed throughout plants in the form of sucrose. Sucrose transporter proteins (SUT) play a crucial role in transporting sucrose. We isolated a cDNA encoding a sucrose transporter,
GmSUT1, which is expressed in the developing cotyledons of soybean (
Glycine max). [
14C]sucrose uptake assays demonstrate that
GmSUT1 has a
K
m
of 5.6
mM and a
V
max of 5.8
nmol sucrose
min
−1
(
mg
cells
)
−1
, which are similar to those of the low-affinity–high-capacity sucrose transporter family.
GmSUT1 protein accumulates gradually during cotyledon development, correlating with increasing sucrose levels in the maturing cotyledons. Collectively, these data suggest that
GmSUT1 plays an active role in the movement of sucrose into the developing seeds.