Oligomeric enzymes in the C4 pathway of photosynthesis

Podestá, Florencio E.; Iglesias, Alberto A.; Andreo, Carlos S.

doi:10.1007/bf00033129

Cited by 20 publications

(7 citation statements)

References 75 publications

(58 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Crude leaf extract and molecular mass standards were subjected to SDS-PAGE (Laemmli 1970) and stained with Coomassie Blue. Optical density of bands at ca 55 kDa (Rubisco large subunit; Andrews and Lorimer 1987) and 96 kDa (PEPC and PPDK;Podesta et al 1990) was then determined. The identity of the 55-kDa band as the Rubisco large subunit was confirmed by westem blotting and antibody probe.…”

Section: Soluble Photosynthetic Enzyme Contentmentioning

confidence: 99%

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

Heckathorn

DeLucia

Zielinski

1997

Physiologia Plantarum

View full text Add to dashboard Cite

The contribution of drought-related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses While stomatal closure usually limits photosynthesis during drought, our previous results suggest that drought-related decreases in foliar nitrogen concentration (NL) limit photosynthesis during recovery from drought in prairie grasses. Here we estimate the importance of decreases in NL to decreased photosynthetic capacity (PSeap) during drought and a subsequent recovery period in three perennial C4 prairie grasses. PScap (O2 evolution at light and CO2 saturation) decreased 69 to 78% during drought in these grasses, and full recovery of PS^ap required 8 to 12 days, until younger leaves were expanded or older leaves were repaired, depending on species. Decreases in NL explained 38 to 51% of the loss of PScap during drought and accounted for 51 to 69% of the total loss of PS^ap integrated over the post-drought recovery period. N-related loss of PScap appeared to result more from decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), phosphoenolpyruvate carboxylase (4.1.1.31), and other soluble photosynthetic enzymes, than from decreases in thylakoid N-containing compounds. Decreases in quantum yield of O2 evolution and Fv/Fn, (variable-to-maximum fluorescence of dark-adapted leaves) during drought were small, so we assumed that little damage to photsystem II (PSII) and thylakoid membrane function occurred. Further, Fo (minimum F) decreased or remained unchanged, dark Fo was greater than light Fo, and decreases in photochemical quenching (the fraction of oxidized PSII) were reversed within 1-3 days after drought. Therefore, prolonged increases in nonphotochemical quenching (q,,; thermal dissipation of excess light energy) during and after drought were indicative of protective downregulation and were likely associated with disproportionate loss of soluble photosynthetic proteins during drought. In support of this, post-drought recovery of qn paralleled recovery of NL and PScap. Thus, in C4 prairie grasses, loss of PS^ap during drought is largely the result of decreases in shoot NL and of associated protective downregulation, decreasing carbon assimilation for 1 -2 weeks after drought.

show abstract

Section: Soluble Photosynthetic Enzyme Contentmentioning

confidence: 99%

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

Heckathorn

DeLucia

Zielinski

1997

Physiologia Plantarum

View full text Add to dashboard Cite

show abstract

“…Some workers do not find changes in the size of the molecule under conditions that are thought to result in different activities. We and others using HPLC and light scattering have found that PEPC has a diurnal change in size (1,17,18) and aggregates or disaggregates under the influence of ligands and other treatments that result in differing activities (10,(12)(13)(14).…”

mentioning

confidence: 99%

Oligomerization and Regulation of Higher Plant Phosphoenolpyruvate Carboxylase

Willeford¹,

Wedding²

1992

Plant Physiol.

View full text Add to dashboard Cite

The specific activity of phosphoenolpyruvate (PEP) measured at a saturating level of substrate diminishes as the enzyme is diluted at about the same rate that specific light scattering by the diluted enzyme decreases. The presence of PEP in the assay causes an increase in activity with increasing dilution. This is accompanied by an increase in light scattering of the diluted enzyme. The reverse situation obtains with the addition of malate to assays: the activity decreases with increasing dilution but light scattering is not substantially changed, indicating that the enzyme is already brought to a smaller aggregate by the dilution itself. In this case, the inhibition by malate in the assay probably is the noncompetitive type not involved in regulatory control by malate. Glucose-6-phosphate in the range from 1 to 6 millimolar causes an increase in activity of the enzyme run at a substrate level less than K,, and an associated increase in light scattering is found, indicating an increase in the mean size of the enzyme. When PEP is added to a 1/80 diluted enzyme, light scattering increases and is associated with a more rapid activity of the enzyme. When malate is added to the same cuvette, the activity decreases and the light scattering diminishes, thus showing that the ligand response is immediately reversible. When malate is added first, followed by PEP, the reverse sequence of activity and light scattering change is observed.

show abstract

“…We found negative coooperativity in the binding of Mg" at pH 7,0 and 8,0 (Tabs 1 and 2) as was described for malic enzyme from sugar cane (Iglesias and Andreo 1990) as well as in the binding of Mn" at pH 7,0, Previous studies have also shown the existence of differ-ent non-equivalent binding sites in malic enzyme from pigeon liver for Mn" at pH 7,0 (Hsu et al, 1976), The biphasic double-reciprocal plots obtained for Mg", Mn-* and Co" (Figs 1 and 2) might also be due to ehange in aggregation state of the enzyme as has been reported for NAD*-malic enzyme and NADP*-malic enzyme (Iglesias and Andreo 1990b, Podesta et al, 1990), All of the activating metal ions (Mg", Mn", Co" and Cd") have ionic radii of 0,86-1,09 A as well as a preference for octahedral coordination geometry. The ions that act as inhibitors are outside the observed range of the activators and/or are incapable of octahedral coordination.…”

Section: Metal Ion I Mmmentioning

confidence: 65%

Interaction of divalent metal ions with the NADP⁺‐malic enzyme from maize leaves

Drincovich

Iglesias

Andreo

1991

Physiologia Plantarum

Self Cite

View full text Add to dashboard Cite

The effect of several metal ions on NADP+‐malic enzyme (EC 1.1.1.40) purified from Zea mays L. leaves was studied Mg2+, Mn2+, Co2+ and Cd2+ were all active metal cofactors. The malic enzyme from maize has a moderately high intrinsic preference for Mn2+ relative to Mg2+ at pH 7.0 and 8.0 Negative cooperativity detected in the binding of Mg2+ at pH 7.0 and 8.0 and in the binding of Mn2+ at pH 7.0 suggests the existence of at least two binding sites with different affinity. All of the activating metal ions have preference for octahedral coordination geometry and have ionic radii of 0.86–1.09 Å. The ions that act as inhibitors are outside this range and/or are incapable of octahedral coordination. Ba2+, Sr2+, Cd2+, Ca2+, Be2+, Ni2+, Cu2+, Zn2+, Co2+, Hg2+ showed mixed‐type inhibition. The reciprocal of their K1 values follow the order of their apparence in the Irving‐Williams series of stability that derives in part from size effects. It is suggested that the size of the ions may play a partial role in determining the strength of the metal interaction.

show abstract

Oligomeric enzymes in the C4 pathway of photosynthesis

Cited by 20 publications

References 75 publications

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

Oligomerization and Regulation of Higher Plant Phosphoenolpyruvate Carboxylase

Interaction of divalent metal ions with the NADP⁺‐malic enzyme from maize leaves

Contact Info

Product

Resources

About

Oligomeric enzymes in the C4 pathway of photosynthesis

Cited by 20 publications

References 75 publications

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses

Oligomerization and Regulation of Higher Plant Phosphoenolpyruvate Carboxylase

Interaction of divalent metal ions with the NADP+‐malic enzyme from maize leaves

Contact Info

Product

Resources

About

Interaction of divalent metal ions with the NADP⁺‐malic enzyme from maize leaves