Unit Definition: 1 Unit causes an increase in absorbance at 260nm of 0.001 per minute per ml at 25°C when acting upon highly polymerized DNA at pH 5.0. Note: Kunitz units as reported by other suppliers can be 2 to 4 times higher than Kunitz units as measured at Worthington. As measured at Worthington, 0.005 Kunitz unit digests 1µg of lambda DNA in 10 minutes at 37°C in 50mM Tris, 1mM Mg²⁺, pH 7.8 in a 50µl reaction. Correlation of digestion units with Kunitz units is different for other DNA and buffer systems.