Purification and characterization of adenosine diphosphate glucose pyrophosphorylase from maize/potato mosaics.

Characterization of an autonomously activated plant ADP-glucose pyrophosphorylase.

ADP-glucose pyrophosphorylase (AGPase) catalyzes the rate-limiting step in starch biosynthesis in plants and changes in its catalytic and/or allosteric properties can lead to increased starch production. Recently, a maize (Zea mays)/potato (Solanum tuberosum) small subunit mosaic, MP [Mos(1-198)], containing the first 198 amino acids of the small subunit of the maize endosperm enzyme and the la...

Heat stability of maize endosperm ADP-glucose pyrophosphorylase is enhanced by insertion of a cysteine in the N terminus of the small subunit.

ADP-glucose pyrophosphorylase (AGPase) is a key regulatory enzyme in starch biosynthesis. However, plant AGPases differ in several parameters, including spatial and temporal expression, allosteric regulation, and heat stability. AGPases of cereal endosperms are heat labile, while those in other tissues, such as the potato (Solanum tuberosum) tuber, are heat stable. Sequence comparisons of heat-...

Purification and properties of the adenosine diphosphate-glucose and uridine diphosphate-glucose pyrophosphorylases of Mycobacterium smegmatis: inhibition and activation of the adenosine diphosphate-glucose pyrophosphorylase.

Crude extracts of Mycobacterium smegmatis catalyzed the synthesis of adenosine diphosphate-glucose (ADP-Glc), cytidine diphosphate-glucose, guanosine diphosphate-glucose (GDP-Glc), thymidine diphosphate-glucose (TDP-Glc), and uridine diphosphate-glucose (UDP-Glc). In these crude enzyme fractions, high concentrations of trehalose-P inhibited the ADP-Glc and GDP-Glc pyrophosphorylases but did not...

THERMOTOLERANT VARIANTS OF MAIZE ENDOSPERM ADENOSINE DIPHOSPHATE GLUCOSE PYROPHOSPHORYLASE By BRIAN TIMOTHY BURGER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE

Starch metabolism in tubers of transgenic potato (Solanum tuberosum) with increased ADPglucose pyrophosphorylase.

The aim of this work was to use tubers from transgenic lines of potato (Solanum tuberosum) containing increased amounts of ADPglucose pyrophosphorylase to study the role of this enzyme in the control of starch synthesis. A 4-5-fold increase in activity of the enzyme, achieved by transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16, had no detectable effect on the s...