Binding of lead to collagen type I and V and alpha(2)(I) CNBr (3,5) fragment by a modified Hummel-Dreyer method

Binding of lead (as lead acetate) to collagen type I alpha(1) and alpha(2) chains, collagen type V and a large cyanogen bromide fragment of type I col lagen [alpha(2)(I)CB3.5] was investigated by the large-zone Hummel-Dreyer m ethod. It was demonstrated that two categories of binding sites exist in th e collagen molecule, the number of which correlates rather well with the av ailable aspartic and glutamic acid residues. Similar results were obtained for all collagen chains (fragments) used. The number of sites thus obtained was compared with the cross-striation pattern (reflecting areas when lead is bound) of the SLS form of collagen type I (alpha(1) chain); it is sugges ted that the number of bands seen in the SLS form reflects primarily the nu mber of available aspartic acid residues in the molecule. The association c onstants obtained are comparable with the low affinity interactions seen e. g., between Cu and bovine serum albumin. (C) 1999 Elsevier Science B.V. All rights reserved.