Subunit structure of three glyceraldehyde 3-phosphate dehydrogenases of some flowering plants

Pupillo, Paolo; Faggiani, Rita

doi:10.1016/0003-9861(79)90653-2

Cited by 69 publications

(36 citation statements)

References 38 publications

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“…This preparation is electrophoretically homogeneous (Fig. 1), with higher specific activity than reported previously (16,22) The enzyme is quite sensitive to freezing and thawing, but it is protected by NADP+ or glycerol (Table II). It is completely stable for at least 1 year if stored at -20C in buffer B (see "Materials and Methods") containing 10% glycerol (v/v), 0.10 mM NADP+, and 5 mm K-phosphate.…”

Section: Resultssupporting

confidence: 47%

“…The GNR was purified from spinach leaves by a method (Table I) derived from Pupillo and Faggiani (22). This preparation is electrophoretically homogeneous (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…GNR affinity for the substrate G3P is high (16,19,22), and the enzyme could act as an effective scavenger of triose phosphate competitive to other cytosolic enzymes including fructose bisphosphate aldolase and NAD-triose phosphate dehydrogenase. This is scarcely compatible with other major metabolisms such as synthesis of sucrose, and it is expected that GNR activity is modulated by metabolites.…”

Section: Nadph Product Inhibition Pattems Indicate Nadph As a Potentmentioning

confidence: 99%

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Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves

Scagliarini

Trost²,

Valenti³

et al. 1990

Plant Physiol.

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The steady state kinetics of glyceraldehyde 3-phosphate:NADP+ oxidoreductase (GNR) (EC 1.2.1.9) have been investigated. The enzyme exhibits hyperbolic behavior over a wide range of substrate concentrations. Double-reciprocal plots are nearly parallel or distantly convergent with limiting Km values of 2 to 5 micromolar for NADP+ and 20 to 40 micromolar for Dglyceraldehyde 3-phosphate (G3P). The velocity response to NADP+ as the varied substrate is however sigmoidal if G3P concentration exceeds 10 micromolar, whereas the response to G3P may show inhibition above this concentration. This 'G3P-inhibited state' is alleviated by saturating amounts of NADP+ or NADPH. Product inhibition pattems indicate NADPH as a potent competitive inhibitor to NADP+ (K, 30 micromolar) and mixed inhibitor towards G3P, and 3-phosphoglycerate (3PGA) as mixed inhibitor to both NADP and G3P (K, 10 millimolar). The data, and those obtained with dead-end inhibitors, are consistent with a nonrapid equilibrium random mechanism with two altemative kinetic pathways. Of these, a rapid kinetic sequence (probably ordered with NADP+ binding first and G3P binding as second substrate) is dominant in the range of hyperbolic responses. A reverse reaction with 3PGA and NADPH as substrates is unlikely, and was not detected. Of a number of compounds tested, erythrose 4-phosphate (Ki 7 micromolar) and Pi (Ki 2.4 millimolar) act as competitive inhibitors to G3P (uncompetitive towards NADP ) and are likely to affect the in vivo activity. Ribose 5-phosphate, phosphoenolpyruvate, ATP, and ADP are also somewhat inhibitory. Full GNR activity in the leaf seems to be allowed only under high photosynthesis conditions, when levels of several inhibitors are low and substrate is high. We suggest that a main function of leaf GNR is to supply NADPH required for photorespiration, the reaction product 3PGA being cycled back to chloroplasts.

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Section: Resultssupporting

confidence: 47%

“…The GNR was purified from spinach leaves by a method (Table I) derived from Pupillo and Faggiani (22). This preparation is electrophoretically homogeneous (Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Nadph Product Inhibition Pattems Indicate Nadph As a Potentmentioning

confidence: 99%

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Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves

Scagliarini

Trost²,

Valenti³

et al. 1990

Plant Physiol.

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“…In some experiments, the enzyme was filtered a third time in the same column, in the absence of NADP+ (enzyme mol wt about 100,000). Procedures for SDSgel electrophoresis (23) and for determination ofmarker enzymes in chromatographic eluates have been described (18,19,22 Reagents were analytical grade. Substrates and proteins used as markers were from Sigma, unless stated otherwise.…”

Section: Methodsmentioning

confidence: 99%

Glucose 6-Phosphate Dehydrogenase Isozymes of Maize Leaves

Valenti¹,

Stanghellini²,

Pupillo³

1984

Plant Physiol.

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Two different forms of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) have been purified from etiolated and green leaves, respectively, of 6-day maize ( Glucose 6-phosphate dehydrogenase of dark-grown maize leaves isoelectric point (pI) 43 is replaced by a form with pI 4.9 during greening.The isozymes show some differences in their kinetic properties, K. of NADP+ being 2.5-fold higher for pI 43 form. Free ATP (K. = 0.64 millimolar) and ADP (K,,= 1.13 millimolar) act as competitive inhibitors with respect to NADPF in pI 4.3 isozyme, and both behave as less effective inhibitors with pI 4.9 isozyme. Magnesium ions abolish the inhibition.Glucose 6-P dehydrogenase in photosynthetic cells of most higher plants occurs as two distinct isozymes, localized in cytoplasm and chloroplasts, respectively, and with comparable activities (1,3,20). The plastid isozyme seems to resemble the cytoplasmic form in several general properties, including mol wt, kinetic properties, and control by certain effectors (1,11,14,20). A single isozyme has, however, been reported for C4 species of the 'malate formers' group (10). It will be shown in this paper that the isozyme of etiolated maize leaves is replaced by a different form during greening, in a way reminiscent of the substitution pattern of isozymes of NADP-dependent malic enzyme (18). The two glucose 6-P dehydrogenase isozymes show minor but distinctive kinetic differences. Subunit structure and association behavior of the purified enzyme are also described, and their resemblances to enzyme from animals and fungi are apparent. MATERIALS AND METHODSMaize plants (Zea mays L. cv Fronica) were germinated as described previously (18). Leaves and coleoptiles of6-d seedlings,

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“…1.2.1.12] catalyzes the reaction of 1,3-bisphosphoglycerate to triose phosphate as the second reaction of the CO 2 reduction cycle. The enzyme is formed by subunits A (36 kDa) and B (39 kDa) in stoichiometric amounts, giving an (A 2 B 2 ) 4 structure of 600 kDa (Pupillo & Faggiani, 1979;Cerff & Chambers, 1979). The two protein subunits, products of the GapP nuclear gene family, show considerable sequence homology.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and preliminary X-ray study of chloroplast glyceraldehyde-3-phosphate dehydrogenase

Sabatino

Fermani

Ripamonti

et al. 1999

Acta Crystallogr D Biol Cryst

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Glyceraldehyde-3-phosphate dehydrogenase from spinach chloroplasts has been crystallized by vapour diffusion in the pH range 7±8.5 in (NH 4 ) 2 SO 4 and Tris±HCl buffer or potassium phosphate buffer at room temperature. Crystals of the A 4 isoform, grown at pH 8.5 in Tris±HCl buffer, diffract to 3.0 A Ê (at 100 K) using synchrotron radiation. The crystals belong to the orthorhombic C222 space group, with unit-cell dimensions a = 145.9, b = 185.9 and c = 106.3 A Ê , and probably contain one tetramer per asymmetric unit. Structure determination by molecular replacement is in progress.

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Subunit structure of three glyceraldehyde 3-phosphate dehydrogenases of some flowering plants

Cited by 69 publications

References 38 publications

Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves

Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves

Glucose 6-Phosphate Dehydrogenase Isozymes of Maize Leaves

Crystallization and preliminary X-ray study of chloroplast glyceraldehyde-3-phosphate dehydrogenase

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Subunit structure of three glyceraldehyde 3-phosphate dehydrogenases of some flowering plants

Cited by 69 publications

References 38 publications

Glyceraldehyde 3-Phosphate:NADP+ Reductase of Spinach Leaves

Glyceraldehyde 3-Phosphate:NADP+ Reductase of Spinach Leaves

Glucose 6-Phosphate Dehydrogenase Isozymes of Maize Leaves

Crystallization and preliminary X-ray study of chloroplast glyceraldehyde-3-phosphate dehydrogenase

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Product

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Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves

Glyceraldehyde 3-Phosphate:NADP⁺ Reductase of Spinach Leaves