Alpha-crystallin-like molecular chaperone against the thermal denaturation of lens aldose reductase: the effect of divalent metal ions.
A chaperone-like activity of bovine lens alpha-crystallin against the thermal-induced aggregation of bovine lens aldose reductase is reported. While the precipitation of aldose reductase at 55 degrees C is prevented by alpha-crystallin present at a ratio of aldose reductase: alpha-crystallin as low as 1:0.5 (w:w), the heat-induced inactivation of the enzyme occurs regardless of the presence of alpha-crystallin. This would suggest that, irrespective of the functional integrity of the target protein, alpha-crystallin interferes only with aggregation phenomena, having the potential to preserve the lens transparency. Calcium and magnesium ions at mM levels affect the antiaggregation action exerted by alpha-crystallin either interfering on the formation or reducing the stability of the aldose reductase: alpha-crystallin complex.
Marini
I
I
Dipartimento di Fisiologia e Biochimica, Università di Pisa, Italy.
Bucchioni
L
L
Voltarelli
M
M
Del Corso
A
A
Mura
U
U
D000449:Aldehyde Reductase / Q000378:metabolism*; D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D002413:Cations, Divalent; D002417:Cattle; D011232:Chemical Precipitation; D003459:Crystallins / Q000378:metabolism / Q000494:pharmacology*; D004795:Enzyme Stability; D006358:Hot Temperature; D007908:Lens, Crystalline / Q000201:enzymology*; D015636:Magnesium Chloride / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology*; D010766:Phosphorylation; D011489:Protein Denaturation / Q000187:drug effects*
D002413:Cations, Divalent; D003459:Crystallins; D008670:Metals; D015636:Magnesium Chloride; D000449:Aldehyde Reductase; D002122:Calcium Chloride