J. Biol. Chem., Vol. 256, Issue 17, 9003-9008, Sep, 1981
Cryoinsolubility of peanut agglutinin. Effect of saccharides and neutral salts
M Decastel, R Bourrillon and JP Frenoy
Peanut agglutinin (PNA) has been shown to be insoluble at low temperatures.
This cryoinsolubility has been studied by means of absorption spectroscopy,
fluorescence, circular dichroism, and analytical ultracentrifugation. It
was found to be dependent on pH, temperature, and protein concentration. No
effects on dimer-tetramer equilibrium could be determined nor any
conformational changes provoked by exposure of the PNA preparation to low
temperatures. The dimer half- molecule apparently does not precipitate. The
cryoinsolubility was partially reversible and totally inhibited in the
presence of galactosides, the specific ligands of PNA. Their efficacy as
inhibitors of cryoinsolubility was related to their affinity for the
lectin. The effects of neutral salts and particularly inhibition of the
insolubility by strongly chaotropic salts indicate that charge-charge
interactions are of little importance and that hydrogen bonds and/or van
der Waals interactions are most probably responsible for the formation of
the cryoprecipitate.
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