This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (38) Citing Articles via Google Scholar Google Scholar Articles by Salminen, S. O. Articles by Young, R. E. Search for Related Content PubMed PubMed Citation Articles by Salminen, S. O. Articles by Young, R. E. Agricola Articles by Salminen, S. O. Articles by Young, R. E.

Articles

The Control Properties of Phosphofructokinase in Relation to the Respiratory Climacteric in Banana Fruit

^a Department of Plant Sciences, University of California, Riverside, California 92502

Glucose 6-phosphate, fructose 6-phosphate, fructose 1, 6-diphosphate, and triose phosphates, and the enzymes phosphofructokinase, aldolase, and glucose 6-phosphate dehydrogenase were extracted from banana fruit (Musa cavendishii, Lambert var. Valery) at the (a) preclimacteric, (b) climacteric rise, (c) climacteric peak, and (d) postclimacteric stages of ripening. The level of fructose 1, 6-diphosphate increased 20-fold whereas the concentration of other intermediates changed no more than 2.5-fold between stages a and c. For these same extracts, phosphofructokinase activity increased 2.5-fold whereas the activity of glucose 6-phosphate dehydrogenase and aldolase changed only fractionally. Substrate saturation studies (fructose 6-phosphate) of phosphofructokinase activity showed a decrease in the [S]_0.5 from 5.6 to 1.7 mM betwen stages a and c. The enzyme from both sources seems to be regulated by a negative cooperative effect with the control being more stringent in the enzyme from stage a. The difference in enzyme activity is consistent with the increase in respiratory activity between the two stages.