Gamma radiation effects on alpha-lactalbumin: structural modifications

alpha -Lactalbumin was irradiated in the lyophilized state in air at ambien t temperature. The irradiated protein was examined by size exclusion chroma tography, sodium dodecyl sulfate polyacrylamide gel electrophoresis, circul ar dichroism, and microcalorimetry. Irradiation induced the loss of aromati c amino acids and of helicity so that fragmentation and aggregation product s were obtained. The thermodynamic properties of the protein were also modi fied. The irradiated protein had lower stability, however, the temperature at which denaturation occurred process remained constant.