Fosfofruktokinaza i kinaza pirogronianowa w tkankach skorupiaków i owadów
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Date
1993
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Wydawnictwo Naukowe Uniwersytetu im. Adama Mickiewicza
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Phosphofructokinase and pyruvate kinase of some crustacean and insect tissues
Abstract
Molecular and kinetic properties of phosphofructokinase and pyruvate kinase of crustacean midgut gland,
hypodermis, muscle and heart as well as of insect fat body and flight, body wall and heart muscles have been
characterized and compared. The results suggest that the reaction catalyzed by the phosphofructokinase is the
most important point for glycolysis regulation in all studied tissues. The phosphofructokinases exist in different
interconvertible molecular forms and their activity is regulated by several positive and negative effectors. It is
suggested that fructose-2,6-bisphosphate is the most powerful one and it plays a role of the signal which turns
the glycolysis on. The pyruvate kinase is also a regulatory enzyme but only in those tissues for which gluconeogenesis
is postulated, that is in the crustacean midgut gland and hypodermis as well as in the insect fat body. In
these tissues, the enzyme is found in different molecular forms, which are characterized by higher or lower activity
in different physiological stages of the tissue. A mechanism of interconversion between them has been
explained and the existence of forms of lower activity has been connected with those stages for which gluconeogenesis
operation is expected. In strictly glycolytic tissues like crustacean abdominal muscle or insect flight
muscle, pyruvate kinase exists in a singular molecular form of high activity. The role of the phosphofructokinase
and pyruvate kinase in the carbohydrate metabolism regulation of particular tissues is discussed.
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Lesicki A., Fosfofruktokinaza i kinaza pirogronianowa w tkankach skorupiaków i owadów, Wydawnictwo Naukowe Uniwersytetu im. Adama Mickiewicza, Poznań 1993, s.161.
ISBN
83-232-0508-6