ISSN:
1432-136X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Oxygen equilibria, ligand-binding kinetics and some other physicochemical properties are reported for erythrocruorins of two intertidal polychaetes:Marphysa sanguinea, which inhabits simple, relatively stagnant burrows, andDiopatra cuprea, which inhabits impermeable, parchment-like tubes that are vigorously ventilated.Marphysa erythrocruorin has a higher O2 affinity, which is less pH dependent (at pH 7.3 and 20°C, half-saturation O2 tension,P 50, and Bohr factor, ϕ=ΔlogP 50/ΔpH, are 0.8 mm Hg and −0.25, respectively) than the corresponding parameters (P 50=5.5; ϕ=−0.86) inDiopatra (Figs. 1 and 2). In contrast to vertebrate haemoglobins, inorganic salts increase erythrocruorin O2 affinity (Fig. 3). The kinetic rates of ligand binding and dissociation ofMarphysa andDiopatra erythrocruorins (Tables 1 and 2) correlate well with the measured O2 affinities and appear to illustrate basic molecular adaptations of the two species to their respective micro-environmental conditions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00687847
Permalink
