4-hexylresorcinol (4HR) was a potent inhibitor of mushroom tyrosinase
in crude extracts, causing 90% loss of activity at 100 muM. The concen
tration of 4HR needed to cause 50% inhibition (I50) was almost-equal-t
o 5 muM. Partially purified tyrosinase was inhibited by lower concentr
ations of 4HR and was characterized with an I50 of almost-equal-to 1 m
uM. Electrophoretic analysis, coupled with isoenzyme staining in the p
resence and absence of 4HR, showed inhibition of tyrosinase isoforms b
ut not of laccase isoforms.