J. Biol. Chem., Vol. 255, Issue 12, 5834-5837, 06, 1980
Charge forms of Wistar rat alpha-lactalbumin. A contradiction
R Prasad and KE Ebner
alpha-Lactalbumin was purified from the milk of Wistar rats and was
compared to that obtained from Fisher 344 rats. alpha-Lactalbumin isolated
from the Wistar rat exists as two forms which differ in their sialic acid
content, as the desialyated forms migrate to one identical position on
polyacrylamide gels. These two charge forms are identical with the charge
Forms II and III previously characterized from Fisher rat
alpha-lactalbumin. No evidence was found to verify previous reports that
one form of the Wistar rat alpha-lactalbumin had a higher molecular weight
than the other form. Indeed, the molecular weights and the amino acid
compositions of the two forms of Wistar rat alpha- lactalbumin are
identical. In addition, the partial amino acid sequence at the NH2-terminal
end and the amino acid composition of the COOH- terminal cyanogen bromide
peptide of the two forms are identical. The results in this study
contradict those reported previously and show that rat alpha-lactalbumin
exists as a single molecular weight species.