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. Author manuscript; available in PMC: 2007 Jul 5.
Published in final edited form as: Bone. 2007 Jan 25;40(5):1343–1351. doi: 10.1016/j.bone.2007.01.011

Figure 2.

Figure 2

Biochemical analysis of collagen

A) Collagen types synthesized by the SAOS-2 cell line in culture

The medium and cell layer on pepsin digestion showed types I and V collagen α-chains on SDS-PAGE. The α1(I) and α2(I) chains ran slightly slower than pepsin extracted control preparations from human bone, suggesting post-translational over-modification. Mass spectrometry identified the band between the α1(V) and α2(V) to be a degradation product of the α1(V) chain. Bands marked “β” are dimers of collagen chains.

B) Identification of α1(XI) collagen chains by mass spectrometry

SDS-PAGE (6%) of collagen extracted by 1M NaCl from the extracellular matrix of SAOS-2 cells (+DTT). Arrow indicates a band identified as a pro-form of the α1(XI) collagen chain. The sequence of a tryptic peptide from this band unequivocally identified by mass spectrometry is shown. Mass spectrometry also identified pro-forms of α1(V) and α2(V), as well as processed α1(I) and α2(I) from this gel. Bands marked “β” are dimers of collagen chains.