PureCol Type I Collagen

The purity of PureCol^® collagen is determined by SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis in conjunction with bacterial collagenase sensitivity and silver staining techniques with a method sensitivity of 99.9%. It was found that PureCol® collagen is 95 to 98% Type I collagen and the remainder being comprised of Type III collagen.

SDS polyacrylamide gel electrophoresis demonstrates the presence of alpha, beta and gamma components in an appropriate ratio of approximately 40:30:30, respectively. PureCol^® collagen is a native collagen as judged by polarimetry and trypsin sensitivity although the product does contain a low percentage of collagen fragments or shortened helices.

Conclusion: With the test method sensitivity of 99.9% (SDS-PAGE gel electrophoresis in conjunction with bacterial collagenase sensitivity and silver staining techniques) and no other proteins present in the preparation, it can be concluded that the purity of the PureCol^® collagen is 99.9%.

The viscosity of PureCol^® is ~32 cp.

PureCol^® product has an isoelectric zone instead of isoelectric point. The isoelectric zone is pH 7 to 8. In addition, the collagen molecules in the PureCol® product will come out of solution starting at a pH above 5.5 and reach its plateau at pH 7 to 8 then gradually tapering off at pH 8 to 9.5.

Reduction of a commercially available, pepsin-solubilized, bovine dermal collagen (Vitrogen 100) (PureCol’s old product name) with sodium [3H]borohydride provided radiolabeled collagen preparations with specific activities ranging from 7.1-12.0 muCi/mg collagen. These specific activities were 2-3 times greater than those obtained by reduction of intact rat tail tendon collagen under similar conditions.

The alpha, beta, and higher aggregate components of type I collagen were radiolabeled as well as the alpha component of a small amount of type III collagen present in the samples. Fractionation of cyanogen bromide peptides showed that alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB3,5 were the predominant peptides labeled by this procedure. Amino acid analysis indicated that the majority of the radioactivity was in reducible cross-links, precursors of these cross-links, and in hexosyllysine residues.

Reconstitution experiments comparing this radiolabeled collagen with nonlabeled collagen showed them to be indistinguishable. Bacterial collagenase digestion of this reconstituted fibrillar collagen in both a lightly cross-linked (glutaraldehyde 0.0075%) and noncross-linked form provided evidence that digestion of labeled and nonlabeled collagens proceeded at similar rates. Thus, labeling did not change the properties of the collagen. Cross-linking made the preparation refractory to proteolytic degradation. Injection of fibrillar collagen preparations, spiked with radiolabeled collagen, into the guinea pig dermis followed by quantitation of the amount of radioactivity recovered from implant sites as a function of time, indicated that the lightly cross-linked samples also were more resistant to degradation in vivo than the noncross-linked preparation.

The half-life of noncross-linked collagen was about 4 days while that of the cross-linked collagen was about 25 days. These degradation rates were much faster than observed for similar, nonlabeled samples injected into the dermis of humans, presumably due to a higher metabolic activity in the guinea pig dermis.

Since the collagen in PureCol collagen contains approximately 95% Type I bovine collagen and 5% Type III bovine collagen, an anti-bovine collagen Type I antibody for your study can be used.

There is no difference. Vitrogen was the old tradename, and PureCol^® is the new tradename.