Purity ~95% (SDS-PAGE). Purified by serial salt precipitations of a pepsin extraction of human fetal membranes and chromatography on DEAE-cellulose. Negative for HBsAG and HIV antibodies. Contaminants: <2% collagen type I, <1% collagen type III, <2% collagen type IV and <0.5% non-collagen proteins. Molecular composition: (a1(V))2 a2(V), native triple helix. Purity and retention of native helical structure was monitored by SDS-PAGE, ORD measurement, and by reaction with anti-collagen type-specific monoclonal antibodies.