Purification and properties of adenosine diphosphoglucose pyrophosphorylase from sweet corn

A 40-fold purification of adenosine diphosphoglucose pyro-phosphorylase from sweet corn (Zea mays var. Golden Beauty) revealed the enzyme to be specific for adenosine triphosphate. The enzyme has an absolute requirement for Mg2+ and is activated by 3-phosphoglycerate and to a lesser extent by ribose...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1972-06, Vol.49 (6), p.893-897
Main Authors: Amir, J, Cherry, J.H
Format: Article
Language:English
Subjects:
Anions
Corn
Diphosphates
Enzyme activity
Enzymes
field crops
Nucleotides
Physiological regulation
plant biochemistry
plant physiology
Quaternary ammonium compounds
Starches
Sulfates
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Summary:A 40-fold purification of adenosine diphosphoglucose pyro-phosphorylase from sweet corn (Zea mays var. Golden Beauty) revealed the enzyme to be specific for adenosine triphosphate. The enzyme has an absolute requirement for Mg2+ and is activated by 3-phosphoglycerate and to a lesser extent by ribose-5-phosphate and fructose-6-phosphate. The apparent Km values of the enzyme for glucose-1-phosphate, adenosine triphosphate, pyrophosphate, and adenosine diphosphoglucose are 1.9 × 10-4, 3.2 × 10-5, 3.3 × 10-5, and 6.2 × 10-4 M, respectively. Pyrophosphate inhibits adenosine diphosphoglucose synthesis competitively (Ki = 3.8 × 10-7 M), while orthophosphate and sulfate appear to inhibit the reacion noncompetively. These results show that the production of this sugar nucleotide can be controlled by the concentration of pyrophosphate.
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.49.6.893