Regulation of Starch Synthesis: Enzymological and Genetic Studies

Preiss, Jack; Bloom, Mark; Morell, Matthew K.; Knowles, Vicki L.; Plaxton, William C.; Okita, Thomas W.; Larsen, Ray A.; Harmon, Alice C.; Putnam-Evans, Cindy

doi:10.1007/978-1-4684-5329-4_12

Cited by 17 publications

(31 citation statements)

References 26 publications

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“…ADGase from all sources is found to be a tetrameric structure (Smith-White and Preiss, 1992) with a size ranging from about 200-240 kDa (Copeland and Preiss, 1981;Preiss et al, 1987). However, the bacterial enzyme is homotetrameric in structure (Haugen et al, 1976), whereas the plant enzyme comprises two subunits Okita et al, 1990;Preiss, 1991).…”

Section: Introductionmentioning

confidence: 99%

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Wang

Lue

et al. 1998

The Plant Journal

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SummaryTwo mutants of Arabidopsis have been isolated that affect ADPG pyrophosphorylase (ADGase) activity. Previously, it has been shown that ADG2 encodes the large subunit of ADGase. This study characterizes the adg1 mutant phenotype and ADG1 gene structure. RNA blot analyses indicate that the adg1-1 mutant accumulates transcripts encoding both the large and small subunits of ADGase, while the adg1-2 mutant accumulates only large subunit transcripts. RFLP analysis and complementation of adg1 mutants with the ADGase small subunit gene demonstrate that ADG1 encodes the small subunit. Sequence analysis indicates that adg1-1 represents a missense mutation within the gene. Western blot analysis confirms that adg1 mutants contain neither the large nor the small subunit proteins, suggesting that the presence of functional small subunits is required for large subunit stability.

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Section: Introductionmentioning

confidence: 99%

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Wang

Lue

et al. 1998

The Plant Journal

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“…ADPglucose pyrophosphorylase (ATP: a-glucose-1-P adenylyl-transferase, EC 2.7.7.27) catalyzes an important regulatory step in the biosynthesis of starch and glycogen in plants and bacteria, respectively (2,(16)(17)(18)(19)(20). This enzyme mediates the synthesis of ADPglucose and PPi from ATP and glucose-I-P; the product, ADPglucose, serving as the glucosyl donor in a-glucan synthesis.…”

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confidence: 99%

“…This enzyme mediates the synthesis of ADPglucose and PPi from ATP and glucose-I-P; the product, ADPglucose, serving as the glucosyl donor in a-glucan synthesis. Both the plant and bacterial enzymes are subject to allosteric regulation by small effector molecules 'Supported in part by grants from the U.S. Department of Energy which accumulate during normal carbon metabolism in these organisms (17)(18)(19)(20). Plant ADPglucose pyrophosphorylases are activated by 3PGA4 and inhibited by Pi (1,2,11,15,23).…”

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confidence: 99%

“…In Escherichia coli and Salmonella typhimurium, ADPglucose pyrophosphorylase is encoded by a single gene locus which gives rise to a homotetramer with native and subunit mol wt of 200,000 and 48,000, respectively (19). Recent studies (1,11,20) have shown that the leaf enzyme from higher plants displays much more structural complexity than those present in bacterial cells. The homogeneous purified spinach leaf enzyme possesses a mol wt of 206,000 which resolves into two dissimilar size subunits of 54,000 and 51,000 in denaturing SDS-PAGE (1, 1 1).…”

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confidence: 99%

“…Western blot studies indicate that dissimilar size ADPglucose pyrophosphorylase subunits are present in Arabidopsis (9), wheat, maize, and rice leaf tissue (6). A recombinant cDNA clone for the 51 kD spinach leaf subunit has been isolated and displays significant homology to the bacterial enzyme (20). Moreover, two independently segregating defective leaf ADPglucose pyrophosphorylase mutants, one completely lacking the 54 kD subunit, have been isolated from Arabidopsis (8,9).…”

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confidence: 99%

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The Subunit Structure of Potato Tuber ADPglucose Pyrophosphorylase

Okita¹,

Nakata²,

Anderson³

et al. 1990

Plant Physiol.

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177

125

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ADPglucose pyrophosphorylase has been extensively purified from potato (Solanum tuberosum L.) tuber tissue to study its structure. By employing a modified published procedure (JR Sowokinos, J Preiss [1982] Plant Physiol 69: 1459-1466) together with Mono 0 chromatography, a near homogeneous enzyme preparation was obtained with substantial improvement in enzyme yield and specific activity. In single dimensional sodium dodecyl sulfate polyacrylamide gels, the enzyme migrated as a single polypeptide band with a mobility of about 50,000 daltons. Analysis by two-dimensional polyacrylamide gel electrophoresis, however, revealed the presence of two types of subunits which could be distinguished by their slight differences in net charge and molecular weight. The smaller potato tuber subunit was recognized by antiserum prepared against the smaller spinach leaf 51 kilodalton ADPglucose pyrophosphorylase subunit. In contrast, the anti-54 kilodalton raised against the spinach leaf subunit did not significantly react to the tuber enzyme subunits. The results are consistent with the hypothesis that the potato tuber ADPglucose pyrophosphorylase is not composed of a simple homotetramer as previously suggested, but is a product of two separate and distinct subunits as observed for the spinach leaf and maize enzymes.ADPglucose pyrophosphorylase (ATP: a-glucose-1-P adenylyl-transferase, EC 2.7.7.27) catalyzes an important regulatory step in the biosynthesis of starch and glycogen in plants and bacteria, respectively (2, 16-20). This enzyme mediates the synthesis of ADPglucose and PPi from ATP and glucose-I-P; the product, ADPglucose, serving as the glucosyl donor in a-glucan synthesis. Both the plant and bacterial enzymes are subject to allosteric regulation by small effector molecules 'Supported in part by grants from the

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