Isolation, characterization and localization of partial small and large subunits of the adp-glucose pyrophosphorylase gene from sago palm (metroxylon sagu)

Adenosine-5'-diphosphoglucose pyrophosphorylase (AGPase) is the allosterically regulated enzyme that catalyzes the rate-limiting step in starch synthesis. Plant AGPases are heterotetrameric with various isoforms exhibiting distinct properties. The objective of this research is to study large s...

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Bibliographic Details
Main Author: Chong, Patricia Ing Pei
Format: Thesis
Language:English
Published: 2008
Subjects:
Online Access:http://ir.unimas.my/id/eprint/28262/1/Patricia%20Chong%20Ing%20Pei%20ft.pdf
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Summary:Adenosine-5'-diphosphoglucose pyrophosphorylase (AGPase) is the allosterically regulated enzyme that catalyzes the rate-limiting step in starch synthesis. Plant AGPases are heterotetrameric with various isoforms exhibiting distinct properties. The objective of this research is to study large subunits of AGPase of sago palm (Metroxylon sagu). In an attempt to learn more about the organization and expression of the small and largesubunit genes of AGPase, I have isolated the partial small and large-subunit gene and cDNA encoding this enzyme in sago palm from the pith and leaf tissues. Through RTPCR screenings of the leaf and pith samples using specific primers that were used to amplify agpll9 and agppl2 respectively, the leaf and pith cDNAs identified by Au and colleagues (2002), similar nucleic acid sequences of agp119 in both leaf and pith cDNAs have been revealed. Semi-quantitative analysis has previously suggested that the large subunit agpl19 was detected only in the leaves of the sago palm (Au et al., 2002). However, this study has managed to isolate, clone and subsequently sequenced cDNAs not only in young and mature leaves but also in the starchy pith revealing the expression of agp119 in both leaf and pith. The 3' end of the partially sequenced agpll9 of leaf has also been identified using RNA Ligase Mediated Rapid Amplification of cDNA Ends (RLM-RACE) and two possible isoforms of agppl2 found in pith have been isolated and subjected to analysis.