The values of Km and Vmax of the citrus esterase for the hydrolysis of p-nitrophenyl acetate were 1.9×10-3M and 250μmol/min·mg, respectively. The enzyme was stable in the pH range from 4.5 to 6.0 and temperature range from 0 to 30°C but was quickly denatured at pH values below 4.5 or over 6.0. Its activity considerably decreased on lyophilization. The enzyme was completely inactivated by sodium dodecylsulfate. It was also inhibited by cetyltrimethylammonium bromide, Brij-35, Tween 80, and Triton X-100, and the enzymatic activity decreased with their increasing concentrations. It was strongly inhibited by diisopropylfluorophosphate and HgCl2. N-Ethylmaleimide, p-chloromercuribenzoic acid, phenylmethanesulfonyl fluoride, p-bromophenacyl bromide, phenylglyoxal, N-tosyl-L-phenylalanyl chloromethyl ketone, N-tosyl-L-lysyl chloromethyl ketone, and ethylenediaminetetraacetic acid showed no significant effect on the enzymatic activity at pH 5.5. The enzyme was inactivated with incorporation of 0.96 mol 208HgCl2 per mol enzyme but did not react with p-[208H] chloromercuribenzoic acid.
