The oxidation of 4-t-butylcatechol catalyzed by mushroom tyrosinase was inhibited by 4-bromobenzaldehyde, 4-chlorobenzaldehyde, 4-fluorobenzaldehyde, 4-cyanobenzaldehyde, and 4-nitrobenzaldehyde with 50% inhibitory concentrations of 114 μM, 175 μM, 387 μM, 822 μM, and 1846 μM, respectively. The inhibition kinetics were analyzed by Dixon plots, which indicated that a series of 4-hallogenated benzaldehydes acted as partial noncompetitive inhibitors in the same manner as benzaldehyde. Although β values were decreased with an increase of the tyrosinase inhibitory activity, full inhibition could not be observed. In contrast, 4-cyanobenzaldehyde and 4-nitrobenzaldehyde acted as mixed and noncompetitive inhibitors, respectively. Full inhibition was particularly represented by 4-nitrobenzaldehyde. According to a previous report, 4-alkylbenzaldehyde and 4-alkoxybenzaldehyde with a bulky substituent acted as full inhibitors. Those results suggested that the steric factor at the 4-position triggered the alternation between partial or full tyrosinase inhibition irrespective of electronic or hydrophobic effects.

蘑菇酪氨酸酶催化的4-叔丁基邻苯二酚的氧化被4-溴苯甲醛，4-氯苯甲醛，4-氟苯甲醛，4-氰基苯甲醛和4-硝基苯甲醛抑制，抑制浓度为50％，分别为114μM，175μM，387μM，分别为822μM和1846μM。通过狄克逊图分析了抑制动力学，表明一系列4-卤代苯甲醛以与苯甲醛相同的方式充当部分非竞争性抑制剂。虽然β随着酪氨酸酶抑制活性的增加，该值降低，不能观察到完全抑制。相反，4-氰基苯甲醛和4-硝基苯甲醛分别充当混合和非竞争性抑制剂。完全抑制作用特别以4-硝基苯甲醛为代表。根据先前的报道，具有大取代基的4-烷基苯甲醛和4-烷氧基苯甲醛充当完全抑制剂。这些结果表明，不管电子或疏水作用如何，在4-位的空间因子触发部分或完全酪氨酸酶抑制作用之间的交替。