Figure 3.

Quantification of site-specific 3-Hyp in type I collagen secreted from ZF4 cells. After pepsin treatment of culture media of ZF4 cells at 4 °C, collagen was purified through salt precipitation. Purified collagen was heat denatured and trypsin digested. LC-MS analysis was performed to quantify 3-Hyp at specific sites (indicated as boldface letters in the sequences). O indicates 4-Hyp. Values are means ± SD (n = 3). Differences of means in the 0 × 3-Hyp (unmodified Pro) were assessed by one-way ANOVA followed by Tukey’s post hoc test.