Type I collagen accounts for more than 90% of the organic matrix of bone and is synthesised primary in bone.
During renewal of the skeleton bone matrix is degraded and consequently fragments of type I collagen are released into circulation. The RatLaps? (CTX-I) EIA is based on the observation that certain C-telopeptide degradation products from type I collagen released during osteoclastic bone resorption.
The RatLaps? (CTX-I) EIA is based upon the competitive binding of a polyclonal antibody to soluble RatLaps antigens EKSQDGGR or to immobilised RatLaps antigens. Briefly, the polyclonal antibody is raised against a synthetic peptide having a sequence (EKSQDGGR) specific for a part of the C-terminal telopeptide α1 chain of rat type I collagen.
For standardisation of the RatLaps? (CTX-I) EIA a synthetic peptide (EKSQDGGR) that is specific for the C-terminal telopeptide α1 chain of type I collagen in rats has been used.