Purity ≥99% by SDS-PAGE. Background value is less than 0.1% (free fluorescence intensity (FI) extracted with 35% ethanol at 25°C). FITC-labeled bovine type I is an excellent substrate for examining collagenase activity. This labeled substrate is highly purified and telo-peptide free. To minimize background levels in collagenase assays, FITC-labeled collagen has been enzymatically pre-treated and further purified by ion-exchange chromatography. Applications: Suitable for use in the assay of mammalian collagenase activity. Solubility: FITC-bovine type I collagen is soluble in acidic buffer (maximum 4mg/ml), but difficult to dissolve in neutral buffer. In order to dissolve in neutral buffer, dissolve in 0.01M acetic acid at 4mg/ml, and then add into neutral buffer (final NaCl concentration should be 0.15-0.2M). FITC-bovine type I collagen forms stable gel in neutral buffer and can be used as a substrate for assaying collagenase activity by collagen-gel method.