If you need an accessible version of this item please contact JSTOR User Support

Maximal Activities of Enzymes of Energy Metabolism in Cephalopod Systemic and Branchial Hearts

William R. Driedzic, Bruce D. Sidell, J. M. Stewart and Ian A. Johnston
Physiological Zoology
Vol. 63, No. 3 (May - Jun., 1990), pp. 615-629
Stable URL: http://www.jstor.org/stable/30156232
Page Count: 15
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Maximal Activities of Enzymes of Energy Metabolism in Cephalopod Systemic and Branchial Hearts
Preview not available

Abstract

The maximal in vitro activities of enzymes of energy metabolism were assessed in systemic ventricle and the branchial hearts of the cephalopods Loligo forbesi, Sepia officinalis, Eledone cirrhosa, and Octopus vulgaris. Within each species, activity levels of enzymes of glycolysis (hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase, and octopine dehydrogenase), citrate synthase, cytochrome oxidase, and total ATPase were higher in the systemic ventricle than in branchial hearts. The greater metabolic potential is consistent with the higher levels of pressure development and subsequent energy demand in the ventricle than in branchial hearts. The systemic ventricle is nourished by oxygenated blood, whereas branchial hearts receive deoxygenated venous blood. Despite differences in oxygen delivery, there is no suggestion from the enzyme profile that anaerobic metabolism is enhanced in branchial hearts. Pairwise regressions were assessed for all marker enzymes from ventricles and branchial hearts of the four species. There are strong linear correlations between phosphofructokinase and citrate synthase activities, and between hexokinase and cytochrome oxidase activities. This suggests that, as interspecific demand for carbon to support the citric acid cycle is increased, there is a concomitant expansion of carbohydrate flux. Consideration of the ventricle alone reveals higher activity levels of phosphofructokinase, citrate synthase, and ATPase in decapods than in octopods. This is consistent with the greater sustainable swimming capability of the former group and may reflect maximum rates of cardiac energy metabolism.

Page Thumbnails

  • Thumbnail: Page 
615
    615
  • Thumbnail: Page 
616
    616
  • Thumbnail: Page 
617
    617
  • Thumbnail: Page 
618
    618
  • Thumbnail: Page 
619
    619
  • Thumbnail: Page 
620
    620
  • Thumbnail: Page 
621
    621
  • Thumbnail: Page 
622
    622
  • Thumbnail: Page 
623
    623
  • Thumbnail: Page 
[624]
    [624]
  • Thumbnail: Page 
625
    625
  • Thumbnail: Page 
626
    626
  • Thumbnail: Page 
627
    627
  • Thumbnail: Page 
628
    628
  • Thumbnail: Page 
629
    629