Effects of temperature, concentration and carboxymethylation on interactions of calf lens crystallins

• Published in: Experimental eye research Vol. 28; no. 6; pp. 717 - 731
• Main Author: Li, Lu-Ku
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.1979
• Subjects: Amino Acids - analysis; Animals; carboxymethylation; Cattle; Chromatography, Gel; concentration dependence; Crystallins - isolation & purification; Electrophoresis, Polyacrylamide Gel; gel filtration; Iodoacetates - pharmacology; lens crystallins; protein interaction; sulfhydryl; Temperature; temperature perturbation; concentration dependence; gel filtration; sulfhydryl; protein interaction; lens crystallins; carboxymethylation; temperature perturbation
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/0014-4835(79)90072-1

Concentration and temperature dependent interactions of calf cortical crystallins were studied by means of gel filtration and disc gel electrophoretic analyses. Low temperature (8°C) gel filtration of either low or high levels of cortical crystallin extracts (5–59 A 280 units) yields elution profiles that are indistinguishable in the distributions of α-, β H-, β L- and γ-crystallins. Gel filtration of low levels of extracts between 22 and 44°C causes a gradual but ultimately complete temperature-dependent disappearance of the region of β H-crystallins and to a lesser degree in the γ-crystallin peak. Chromatography of high levels of extracts at 44°C results in the reappearance of a high mol. wt. β-crystallin peak with electrophoretic property and polypeptide composition different from those of β H-crystallin isolated at the low temperature of 8°C. Preincubation of high levels of extracts at 44°C causes some small but irreversible changes in the elution profile obtained at 8°C. Taken together these results suggest that the presence of high mol. wt. β-crystallin is the result of largely reversible equilibria between β-crystallins and other lenticular components. The reaction of calf cortical extracts with increasing amounts of iodoacetic acid results in a progressive loss in the β H-crystallin region of the 8°C filtration profile. Results from amino acid analyses and sodium dodecylsulfate (SDS) gel electrophoreses of the respective α-, β L- and γ-crystallin fractions indicate that the SH moieties of the cysteine residues are essential to the formation of high mol. wt. β-crystallins.