Variation among species in light activation of sucrose-phosphate synthase

Steven C Huber, Tom Hamborg Nielsen, Joan L.A. Huber, David M. Pharr

Research output: Contribution to journalArticle

Abstract

Some species exhibit light activation of sucrose-phosphate synthase (SPS) in intact leaves. Twelve species which vary in extent of light modulation of SPS were studied to identify factors which regulate activation of the enzyme in situ. Leaves were harvested in light and darkness, and SPS was assayed under high substrate (Vmax) or limiting substrate conditions (in the presence of th inhibitor inorganic phosphate). The species tested fell into three groups. In some species (Group I; barley and maize) light activation involved an increase in Vmax of the enzyme. In other species (Group II; spinach, swiss chard, sugarbeet, broad bean) light activation had no effect on Vmax but altered certain kinetic properties such that activation was only apparent when SPS was assayed with the limiting substration condition. Significantly, in some species (Group HI; soybean, pea, tobacco, Arabidopsis thaliana cucumber and melon) SPS activity was essentially unaffected by light/dark transitions. Phosphate sequestering agents (mannose or gluco-samine) activated SPS in darkness in species which show light modulation (Groups I and II) but not species of Group III which do not light activate. Thus, changes in inorganic phosphate level may be one of the factors which regulate the activation of SPS in situ. In addition, the catalytic activity of SPS from species which exhibit light modulation (Groups I and II) is more strongly inhibited in vitro by inorganic phosphate (an allosteric effector) compared with the enzyme extracted from Group III species, which indicates that certain properties of the enzyme itself may also vary among species. We conclude that species which do not exhibit light activation of SPS in intact leaves lack the mechanism responsible for the covalent modification of enzyme activity (Walker and Huber 1989, Planta, in press) involved in light activation process.

Original languageEnglish (US)
Pages (from-to)277-285
Number of pages9
JournalPlant and Cell Physiology
Volume30
Issue number2
DOIs
StatePublished - Mar 1989

Fingerprint

sucrose-phosphate synthase
Light
Phosphates
phosphates
Darkness
Enzymes
Sequestering Agents
enzymes
chard
Cucurbitaceae
leaves
Cucumis sativus
enzyme activation
Beta vulgaris
Enzyme Activation
Spinacia oleracea
Peas

Keywords

  • Inorganic phosphate
  • Light activation
  • Maize
  • Soybean
  • Spinach
  • Sucrose-phosphate synthase

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

Cite this

Variation among species in light activation of sucrose-phosphate synthase. / Huber, Steven C; Nielsen, Tom Hamborg; Huber, Joan L.A.; Pharr, David M.

In: Plant and Cell Physiology, Vol. 30, No. 2, 03.1989, p. 277-285.

Research output: Contribution to journalArticle

Huber, Steven C ; Nielsen, Tom Hamborg ; Huber, Joan L.A. ; Pharr, David M. / Variation among species in light activation of sucrose-phosphate synthase. In: Plant and Cell Physiology. 1989 ; Vol. 30, No. 2. pp. 277-285.
@article{e3829f0f644e4f6a9cbfa8141d7f3032,
title = "Variation among species in light activation of sucrose-phosphate synthase",
abstract = "Some species exhibit light activation of sucrose-phosphate synthase (SPS) in intact leaves. Twelve species which vary in extent of light modulation of SPS were studied to identify factors which regulate activation of the enzyme in situ. Leaves were harvested in light and darkness, and SPS was assayed under high substrate (Vmax) or limiting substrate conditions (in the presence of th inhibitor inorganic phosphate). The species tested fell into three groups. In some species (Group I; barley and maize) light activation involved an increase in Vmax of the enzyme. In other species (Group II; spinach, swiss chard, sugarbeet, broad bean) light activation had no effect on Vmax but altered certain kinetic properties such that activation was only apparent when SPS was assayed with the limiting substration condition. Significantly, in some species (Group HI; soybean, pea, tobacco, Arabidopsis thaliana cucumber and melon) SPS activity was essentially unaffected by light/dark transitions. Phosphate sequestering agents (mannose or gluco-samine) activated SPS in darkness in species which show light modulation (Groups I and II) but not species of Group III which do not light activate. Thus, changes in inorganic phosphate level may be one of the factors which regulate the activation of SPS in situ. In addition, the catalytic activity of SPS from species which exhibit light modulation (Groups I and II) is more strongly inhibited in vitro by inorganic phosphate (an allosteric effector) compared with the enzyme extracted from Group III species, which indicates that certain properties of the enzyme itself may also vary among species. We conclude that species which do not exhibit light activation of SPS in intact leaves lack the mechanism responsible for the covalent modification of enzyme activity (Walker and Huber 1989, Planta, in press) involved in light activation process.",
keywords = "Inorganic phosphate, Light activation, Maize, Soybean, Spinach, Sucrose-phosphate synthase",
author = "Huber, {Steven C} and Nielsen, {Tom Hamborg} and Huber, {Joan L.A.} and Pharr, {David M.}",
year = "1989",
month = "3",
doi = "10.1093/oxfordjournals.pcp.a077740",
language = "English (US)",
volume = "30",
pages = "277--285",
journal = "Plant and Cell Physiology",
issn = "0032-0781",
publisher = "Oxford University Press",
number = "2",

}

TY - JOUR

T1 - Variation among species in light activation of sucrose-phosphate synthase

AU - Huber, Steven C

AU - Nielsen, Tom Hamborg

AU - Huber, Joan L.A.

AU - Pharr, David M.

PY - 1989/3

Y1 - 1989/3

N2 - Some species exhibit light activation of sucrose-phosphate synthase (SPS) in intact leaves. Twelve species which vary in extent of light modulation of SPS were studied to identify factors which regulate activation of the enzyme in situ. Leaves were harvested in light and darkness, and SPS was assayed under high substrate (Vmax) or limiting substrate conditions (in the presence of th inhibitor inorganic phosphate). The species tested fell into three groups. In some species (Group I; barley and maize) light activation involved an increase in Vmax of the enzyme. In other species (Group II; spinach, swiss chard, sugarbeet, broad bean) light activation had no effect on Vmax but altered certain kinetic properties such that activation was only apparent when SPS was assayed with the limiting substration condition. Significantly, in some species (Group HI; soybean, pea, tobacco, Arabidopsis thaliana cucumber and melon) SPS activity was essentially unaffected by light/dark transitions. Phosphate sequestering agents (mannose or gluco-samine) activated SPS in darkness in species which show light modulation (Groups I and II) but not species of Group III which do not light activate. Thus, changes in inorganic phosphate level may be one of the factors which regulate the activation of SPS in situ. In addition, the catalytic activity of SPS from species which exhibit light modulation (Groups I and II) is more strongly inhibited in vitro by inorganic phosphate (an allosteric effector) compared with the enzyme extracted from Group III species, which indicates that certain properties of the enzyme itself may also vary among species. We conclude that species which do not exhibit light activation of SPS in intact leaves lack the mechanism responsible for the covalent modification of enzyme activity (Walker and Huber 1989, Planta, in press) involved in light activation process.

AB - Some species exhibit light activation of sucrose-phosphate synthase (SPS) in intact leaves. Twelve species which vary in extent of light modulation of SPS were studied to identify factors which regulate activation of the enzyme in situ. Leaves were harvested in light and darkness, and SPS was assayed under high substrate (Vmax) or limiting substrate conditions (in the presence of th inhibitor inorganic phosphate). The species tested fell into three groups. In some species (Group I; barley and maize) light activation involved an increase in Vmax of the enzyme. In other species (Group II; spinach, swiss chard, sugarbeet, broad bean) light activation had no effect on Vmax but altered certain kinetic properties such that activation was only apparent when SPS was assayed with the limiting substration condition. Significantly, in some species (Group HI; soybean, pea, tobacco, Arabidopsis thaliana cucumber and melon) SPS activity was essentially unaffected by light/dark transitions. Phosphate sequestering agents (mannose or gluco-samine) activated SPS in darkness in species which show light modulation (Groups I and II) but not species of Group III which do not light activate. Thus, changes in inorganic phosphate level may be one of the factors which regulate the activation of SPS in situ. In addition, the catalytic activity of SPS from species which exhibit light modulation (Groups I and II) is more strongly inhibited in vitro by inorganic phosphate (an allosteric effector) compared with the enzyme extracted from Group III species, which indicates that certain properties of the enzyme itself may also vary among species. We conclude that species which do not exhibit light activation of SPS in intact leaves lack the mechanism responsible for the covalent modification of enzyme activity (Walker and Huber 1989, Planta, in press) involved in light activation process.

KW - Inorganic phosphate

KW - Light activation

KW - Maize

KW - Soybean

KW - Spinach

KW - Sucrose-phosphate synthase

UR - http://www.scopus.com/inward/record.url?scp=0002379220&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0002379220&partnerID=8YFLogxK

U2 - 10.1093/oxfordjournals.pcp.a077740

DO - 10.1093/oxfordjournals.pcp.a077740

M3 - Article

AN - SCOPUS:0002379220

VL - 30

SP - 277

EP - 285

JO - Plant and Cell Physiology

JF - Plant and Cell Physiology

SN - 0032-0781

IS - 2

ER -