THE CO2 SENSITIVITY OF THE HEMOCYANINS AND ITS RELATIONSHIP TO Cl- SENSITIVITY
TLDR
While a influences only oxygen affinity, CO2 may influence cooperativity as well and this finding suggests that the effective species is molecular CO2.Abstract:
The effect of CO2 on hemocyanin-oxygen binding is not generally related to the effect of Cl-. Some hemocyanins respond to both and some to either one alone. The direction of the responses of O2 affinity of the various hemocyanins to CO2 is poorly correlated with the direction of responses to other effectors. The influence of CO2 on Busycon and Limulus hemocyanins reaches its maximum at high pH. Since the effect can be abolished by restoring divalent cation activities to the control levels prior to the addition of CO2, we suggest that the effect is not specific but rather indirect, by the pairing of the allosteric effectors Ca+2 and Mg+2 with the CO2 anions. In contrast the effect of CO2 on crustacean hemocyanins is greaterat low pH and it can be enhanced by maintaining HCO3- levels within narrow limits and permitting PCO2 to vary by a large factor. This finding suggests that the effective species is molecular CO2. While a influences only oxygen affinity, CO2 may influence cooperativity as well. Indifferen...read more
Citations
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Future ocean acidification will be amplified by hypoxia in coastal habitats
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Physiological Responses to Hypoxia
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References
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Journal ArticleDOI
A comparison of molluscan and arthropod hemocyanin—I. Circular dichroism and absorption spectra
TL;DR: The circular dichroic spectra of molluscan and arthropod oxyhemocyanins are qualitatively and quantitatively different and indicate fundamental differences in the oxygen binding sites of these related proteins.
Journal ArticleDOI
Ionic regulation in the crab Carcinus maenas (L.) in relation to the moulting cycle
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Journal ArticleDOI
Respiratory Function of the Hemocyanins
TL;DR: With the exception of the crustacean oxygen carrier the hemocyanins confer a respiratory advantage over their predecessors, but the oxygen carrying capacity of crustACEan blood never reaches the levels found in the annelids and molluscs.
Journal ArticleDOI
Functional Differences in the Multiple Hemocyanins of the Horseshoe Crab, Limulus polyphemus L
TL;DR: The kinetics of oxygen combination and dissociation for the various hemocyanin preparations show that variations in the rate of oxygen dissociation are primarily responsible for the observed differences in oxygen affinity.