Collagenase type 4 is partially purified and is designed to be especially low in tryptic activity to limit damage to membrane proteins and receptors. The collagenase assay is a modification of the Mandl collagen digestion procedure wherein collagenase is incubated for five hours with native collagen and the extent of collagen breakdown is determined using the Moore and Stein, JBC, 176, 367, (1948) colorimetric ninhydrin method. Amino acids released are expressed as micromoles L-leucine per milligram collagenase in 5 hours at 37°C, pH 7.5. Caseinase activity, a measure of non-specific proteolytic activity, is determined using the above assay and substituting 25 milligrams vitamin free casein for the collagen substrate. Caseinase activity is calculated as for collagenase activity. Clostripain activity is measured after activation in 2.5 mM dithiothreitol (DTT). One unit hydrolyzes one micromole of BAEE per minute at 25°C, pH 7.6, after activation. Tryptic activity is assayed using the same BAEE method as clostripain, but without activation.
Size
100 mg
Concentration
≥160 CDU/mgdw
Applications
Collagenase Type 4 contain lower tryptic activity levels to limit damage to membrane proteins and receptors but with normal to above normal collagenase activity. It is suggested for pancreatic islet primary isolation. Collagenase is typically used at concentrations from 0.05 % to 0.5 % (w/v) in balanced salt solutions such as Hank's, Earle's and others. For best results the precise mixture of collagenase and proteolytic activities must be tailored to the tissue to be dissociated. Specific conditions for reactivity should be optimized by the end user.