Interactive Effects of Temperature and L-Lactate on the Binding of Oxygen by the Hemocyanin of Two Arctic Boreal Crabs, Hyas araneus and Hyas coarctatus

The effects of changes in temperature (—1.5 to 25 C) and in the concentration ofLlactate on oxygen binding by the bemocyanin of Hyas araneus and H. coarctatus were compared. At temperatures above 15 C the binding of oxygen by both bemocyanins was essentially temperature insensitive, but below 15 C a...

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Bibliographic Details
Published in:	Physiological zoology 1989-01, Vol.62 (1), p.62-82
Main Authors:	Morris, S., Bridges, C. R.
Format:	Article
Language:	eng
Subjects:	Biochemistry. Physiology. Immunology Biological and medical sciences Blood Crabs Crustacea Crustaceans Fundamental and applied biological sciences. Psychology Hemolymph Invertebrates Lactates Low temperature Oxygen Oxygen partial pressure Physiology. Development Temperature dependence Thermodynamic equilibrium
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Summary:	The effects of changes in temperature (—1.5 to 25 C) and in the concentration ofLlactate on oxygen binding by the bemocyanin of Hyas araneus and H. coarctatus were compared. At temperatures above 15 C the binding of oxygen by both bemocyanins was essentially temperature insensitive, but below 15 C and at lowpH the sensitivity increased. Comparing data obtained at temperatures above 10 C with those collected at —1.5 C, the temperature decrease was accompanied by a reduction in the size of the Bohr effect. The Bobrfactor changedfrom approximately —0.7 to —0.3 andfrom —0.8 to —0.SforH. coarctatus andH. araneus hemocyanin, respectively. Temperature changes affected the affinities of the deoxygenatedH. coarctatus hemocyanin to a greater extent than that of the oxygenatedpigment, which was reflected by a decrease in cooperativity. This was due to a depression of the intrinsic affinity$K_{R}$. The effect of lactate on the$P_{50}$of H. araneus bemocyanin was greater than that onH. coarctatus hemocyanin (Δlog$P_{50}$/Δlog[lac⁻] = —0.30 and—0.17, respectively, p 7.8, 25 C). Cooperative oxygen binding by H. coarctatus but not H. araneus bemocyanin was reduced by increased L-lactate. The L-lactate effect exhibited a temperature dependency that was mostpronounced at extreme oxygen saturations. AH dependency of the lactate effect was most apparent at high temperature and low saturation.
ISSN:	0031-935X 1937-4267