G. Benga et al., NMR-STUDIES OF DIFFUSIONAL WATER PERMEABILITY OF RED-BLOOD-CELLS FROMTHE ECHIDNA TACHYGLOSSUS-ACULEATUS, Comparative biochemistry and physiology. B. Comparative biochemistry, 107(1), 1994, pp. 45-50
The diffusional water permeability (P-d) of the red blood cells (RBC)
from echidna (Tachyglossus aculeatus) was measured by a Mn2+-doping H-
1 nuclear magnetic resonance (NMR) technique at 400 MHz. The values of
P-d were relatively low: around 1.9 x 10(-3) cm/sec at 25 degrees C,
2.2 x 10(-3) cm/sec at 29.5 degrees C, 2.9 x 10(-3) cm/sec at 35.2 deg
rees C, 3.2 x 10(-3) cm/sec at 37 degrees C, 3.9 x 10(-3) cm/sec at 40
.5 degrees C and 4.2 x 10(-3) cm/sec at 42 degrees C. In parallel with
the low water permeability the activation energy for the diffusion pr
ocess (E(a,d)) was relatively high, similar to 33 kJ/mol. The membrane
polypeptide electrophoretic pattern of echidna RBC was compared with
its human counterpart. The proteins migrating in bands 3 and 4.1 had l
ower mobilities in echidna compared with human membranes. In the echid
na RBC membranes band 4.1 was not split into 4.1a and 4.1b sub-bands.
Glyceraldehyde 3-phosphate dehydrogenase (band 6) was markedly less in
tense in echidna than in human RBC. The faint bands between 4.2 and 5
and in the band 7-8 region showed considerable differences between the
two species. At low ionic strength the pattern of solubilization of p
roteins from echidna RBC membranes was different from human membranes,
with only a trace of band 4.1 protein extracted from the echidna RBC.