Interaction of alpha-lactalbumin with Cu2+.
1988 (English)In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 32, no 1, 37-42 p.Article in journal (Refereed) Published
It has been shown by intrinsic fluorescence spectroscopy that alpha-lactalbumin has several Cu2+ -binding sites per molecule. The Ca2+ -loaded protein binds two or more Cu2+ per molecule with an association constant of about 3 X 10(3) M-1. Apo-alpha-lactalbumin binds one Cu2+ per molecule with association constant 8 X 10(4) M-1 and from two to three Cu2+ with an association constant of about 4 X 10(3) M-1. The results obtained from spectrofluorometric pH titration of alpha-lactalbumin in the acidic pH region show the possible involvement of histidine residues in the coordination of Cu2+. The binding of Cu2+ to alpha-lactalbumin lowers significantly its thermostability and stability towards urea denaturation. The stability of Cu2+, Ca2+-alpha-lactalbumin against thermal and urea denaturation is similar to that of the apo protein. The thermal transition in Cu2+, Ca2+-alpha-lactalbumin occurs within the region of physiological temperatures which may suggest the existence of some thermal regulation of its functioning in vivo.
Place, publisher, year, edition, pages
1988. Vol. 32, no 1, 37-42 p.
IdentifiersURN: urn:nbn:se:umu:diva-43022PubMedID: 3233312OAI: oai:DiVA.org:umu-43022DiVA: diva2:411137