Plant ADP-Glucose Pyrophosphorylase -Recent Advances and Biotechnological Perspectives (A Review)

Kleczkowski, Leszek A.; Villand, Per; Lönneborg, Anders; Olsen, Odd‐Arne; Lüthi, Ernst

doi:10.1515/znc-1991-7-817

Cited by 34 publications

(23 citation statements)

References 21 publications

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“…Since starch synthase is localized in the plastid stroma (Echeverria et al, 1988), it follows that in btl endosperm cells ADP-Glc accumulates in the cytosol. Kleczkowski et al (1991) and Hannah et al (1993) as well as in the amyloplast stroma, and Villand and Kleczkowski (1994) detailed the evidence in support of this suggestion. A possible explanation is that BT1 is an adenylate translocator, and in its absence (i.e.…”

Section: Discussionmentioning

confidence: 72%

Nucleotides and Nucleotide Sugars in Developing Maize Endosperms (Synthesis of ADP-Glucose in brittle-1)

1996

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As part of an in vivo study of carbohydrate metabolism during development of Zea mays L. kernels, quantities of nucleotides and nucleotide sugars were measured in endosperm extracts from normal, the single-mutant genotypes shrunken-7 (shl), shrunken-2 (shz), and brittle-7 (btl), and the multiple-mutant genotypes shlbtl, shzbtl, and shlsh2btl. Results showed that b t l kernels accumulated more than 13 times as much adenosine 5' diphosphoglucose (ADP-Clc) as normal kernels. Activity of starch synthase in btl endosperm was equal to that in endosperm extracts from normal kernels. Thus the ADP-Clc accumulation in btl endosperm cells was not d u e t o a deficiency in starch synthase. ADP-Clc content in extracts of s h l b t l endosperms was similar t o that in btl, but i n extracts of the sh2btl mutant kernels ADP-Clc content was much reduced compared to b t l (about 3 times higher than that in normal). Endosperm extracts from shlsh2bt7, kernels that are deficient i n both ADP-Clc pyrophosphorylase (ACPase) and sucrose synthase, had quantities of ADP-Clc much lower than in normal kernels. These results clearly indicate that AGPase is the predominant enzyme responsible for the in vivo synthesis of ADP-Clc in b t l mutant kernels, but SUC synthase may also contribute to the synthesis of ADP-Clc i n kernels deficient in ACPase.A number of maize (Zea mays L.) endosperm mutants that affect the quantity and quality of carbohydrates in the endosperm, as well as kernel development and morphology, have been identified and extensively studied (Shannon and Garwood, 1984). Mutants such as waxy (wx), amylose extender (ne), and sugary-l affect the quantity and branching characteristic of kernel polysaccharides (Shannon and Garwood, 1984). Severa1 other mutants involve a defect in the metabolism of sugars, resulting in the accumulation of Suc and the reduction in starch. For example, skl kernels are deficient in the major Suc synthase enzyme (Chourey and Nelson, 1976), and sh2 and brittle-2 mutant kernels are both deficient in AGPase (Preiss, 1991). The genetic lesion of b t l , another high-sugarllow-starch mutant, is not as well defined. Early screening of developing b t l kernels for the activity of various enzymes of carbohydrate metabolism and starch biosynthesis failed to identify a specific enzyme lesion. Developing b t l kernels, compared to normal, have been reported to be low in a starch granule-bound phospho-oligosaccharide synthase (Pan and Nelson, 1985) and starch debranching enzyme but twice as high in AGPase (Doehlert and Kuo, 1990). Sullivan et al. (1991) reported the isolation and analysis of the B t l gene from maize and showed that the protein with greatest similarity to the Btl-encoded protein is a yeast adenylate translocator. Li et al. (1992) showed that the in vitro translated B t l gene product could be imported into chloroplasts, where it was processed and localized to the inner envelope membrane. We have isolated amyloplast membranes from normal and b t l kernels and showed that the four most abundant amylo...

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Section: Discussionmentioning

confidence: 72%

Nucleotides and Nucleotide Sugars in Developing Maize Endosperms (Synthesis of ADP-Glucose in brittle-1)

1996

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“…Whether this allosteric regulation operates in nonphotosynthetic tissue is questionable (Okita et al, 1993). Nevertheless, the AGP enzyme present in nonphotosynthetic tissue, particularly developing sink organs, operates in a highly inhibited environment (Hnilo and Okita, 1989), and there is much interest in the genetic modification of AGP activity to enhance plant productivity by increasing the flow of carbon into starch (Kleczkowski et al, 1991;Stark et al, 1992;Okita et al, 1993).…”

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confidence: 99%

Differential Regulation of ADP-Glucose Pyrophosphorylase in the Sink and Source Tissues of Potato

Nakata

Okita

1995

Plant Physiol.

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Expression of potato (Solanum tuberosum L.) ADP-Clc pyrophosphorylase (ACP) was analyzed to assess whether the expression patterns of the individual subunit genes play a role in effectuating ACP activity and hence starch biosynthesis. Temporal analysis revealed that the coordinate expression of the large (IAGP) and small (sACP) subunits, which collectively make up the heterotetrameric ACP holoenzyme, is primarily under transcriptional control during tuber development. In contrast, noncoordinate expression of the subunit transcripts was evident in leaves in which the relative level of the sACP mRNA was present at severalfold excess compared to the level of IACP mRNA. lmmunoblot analysis, however, revealed that the levels of sACP and IACP polypeptides were present at near equimolar amounts, indicating that a posttranscriptional event coordinates subunit polypeptide levels. This posttranscriptional control of subunit abundance was also evident in leaves subjected to a photoperiod regime and during sucrose-induced starch synthesis. l h e predominant role of transcriptional and posttranscriptional regulation of ACP in tubers and leaves, respectively, is consistent with the distinct pathways of carbon partitioning and with the type and function of starch synthesis that occurs within each tissue.

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“…AGP catalyzes the initial, allosterically regulated reaction in starch biosynthesis in both photosynthetic and nonphotosynthetic tissues and provides a pivotal point at which manipulation of this pathway can take place (Kleczkowski et al, 1991;Okita et al, 1993;Nakata and Okita, 1994). Before we can fully manipulate this enzyme and starch biosynthesis, we must begin to understand how AGP interacts with its substrates and effectors.…”

Section: Discussionmentioning

confidence: 99%

Aspartic Acid 413 Is Important for the Normal Allosteric Functioning of ADP-Glucose Pyrophosphorylase

1996

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As part of a structure-function analysis of the higher-plant ADP-glucose pyrophosphorylase (AGP), we used a random mutagenesis approach in combination with a novel bacterial complementation system to isolate over 100 mutants that were defective in glycogen production (T.W. Greene, S.E. Chantler, M.L. Khan, G.F. Barry, J. Preiss, T.W. Okita [1996] Proc Natl Acad Sci USA 93: 1509–1513). One mutant of the large subunit M27 was identified by its capacity to only partially complement a mutation in the structural gene for the bacterial AGP (glg C), as determined by its light-staining phenotype when cells were exposed to I2 vapors. Enzyme-linked immunosorbent assay and enzymatic pyrophosphorylysis assays of M27 cell extracts showed that the level of expression and AGP activity was comparable to those of cells that expressed the wild-type recombinant enzyme. Kinetic analysis indicated that the M27 AGP displays normal Michaelis constant values for the substrates glucose-1-phosphate and ATP but requires 6- to 10-fold greater levels of 3-phosphoglycerate (3-PGA) than the wild-type recombinant enzyme for maximum activation. DNA sequence analysis showed that M27 contains a single point mutation that resulted in the replacement of aspartic acid 413 to alanine. Substitution of a lysine residue at this site almost completely abolished activation by 3-PGA. Aspartic acid 413 is adjacent to a lysine residue that was previously identified by chemical modification studies to be important in the binding of 3-PGA (K. Ball, J. Preiss [1994] J Biol Chem 269: 24706–24711). The kinetic properties of M27 corroborate the importance of this region in the allosteric regulation of a higher-plant AGP.

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Plant ADP-Glucose Pyrophosphorylase -Recent Advances and Biotechnological Perspectives (A Review)

Cited by 34 publications

References 21 publications

Nucleotides and Nucleotide Sugars in Developing Maize Endosperms (Synthesis of ADP-Glucose in brittle-1)

Nucleotides and Nucleotide Sugars in Developing Maize Endosperms (Synthesis of ADP-Glucose in brittle-1)

Differential Regulation of ADP-Glucose Pyrophosphorylase in the Sink and Source Tissues of Potato

Aspartic Acid 413 Is Important for the Normal Allosteric Functioning of ADP-Glucose Pyrophosphorylase

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