Type I Collagen
The most abundant collagen type, comprising approximately 90% of the body's collagen. Type I collagen provides tensile strength to skin, tendons, bones, and ligaments. It is the primary structural component assessed in tendon and wound healing research relevant to tissue repair peptides.
Technical Context
Type I collagen is a heterotrimer composed of two alpha-1(I) chains and one alpha-2(I) chain, encoded by COL1A1 and COL1A2 genes. Molecular weight: approximately 300 kDa per triple helix, approximately 1.5nm diameter × 300nm length. Mechanical properties: ultimate tensile strength approximately 50-100 MPa (comparable to aluminium wire). Biomarkers of Type I collagen metabolism: formation markers — PINP (procollagen type I N-terminal propeptide, cleaved during extracellular processing) and PICP (C-terminal propeptide); degradation markers — CTX-I (C-terminal crosslinked telopeptide, released during osteoclastic bone resorption) and NTX-I (N-terminal crosslinked telopeptide). These biomarkers are used in osteoporosis trials to monitor bone turnover: PTH analogues (teriparatide, abaloparatide) increase PINP (formation) before increasing CTX-I (resorption), confirming the anabolic window of intermittent PTH therapy.