Water → 2-Nitrophenol

Participants

Reaction Steps

0.05 ml of the standard solution of sodium ion was placed in a test tube. Then, 2.0 ml of 300 mM Tris-HCl buffer (pH 7.4) preheated to 37° C. and containing 1100 unit/l β-galactosidase (Sigma), 3 mM DL-dithiothreitol (Sigma), 11.2 mM magnesium sulfate (Sigma) and 220 mM or 260 mM lithium chloride (Wako Pure Chemicals) was added to the test tube. Then, 1.0 ml of distilled water preheated to 37° C. and containing 1.5 mM o-nitrophenyl β-D-pyranoglycoside (Merck) was added thereto, mixed with agitation, and reacted at 37° C. The amount of o-nitrophenol produced for 1 minute was determined with a spectrophotometer (Hitachi; Model UV3400) based on the absorption intensity of the visible portion at 420 nm. The calibration curves obtained are shown in FIG. 1.

Provenance & Evidence