Figure 3

Extent of Lys hydroxylation at specific sites of type I collagen. (a) Lys hydroxylation in the telopeptides, (b) Lys hydroxylation in the cross-linking and non-cross-linking helical sites (see Table 2). Values represent percentages of Lys hydroxylation calculated as Hyl/(Lys + Hyl) × 100. Hyl in the helical domain is a sum of non-glycosylated, G, and GG-Hyl (see Table 3). Lys lysine, Hyl hydroxylysine, G- galactosyl-, GG- glucosylgalactosyl-, MC MC3T3-E1, EV empty vector, KO knock-out. Values represent mean ± S.D. (n = 3) of triplicate for each group. Statistical differences were determined by the method described above (Fig. 1 legend). *p < 0.05, **p < 0.01, and ***p < 0.001 between MC and KO; ^#p < 0.05, ^##p < 0.01, and ^###p < 0.001 between EV and KO, respectively. The relative levels at α1(I)K918/930 show the percentage of “Hyl + Hyl”. See Table 3.