Identification of Tyrosinase in Mushrooms by Isoelectric Focusing

Isoenzymes of tyrosinase were identified in mushrooms using vertical polyacrylamide gel isoelectric focusing in conjunction with a pH 4‐7 gradient. The M2, M8, and M9 strains of Agaricus could be distinguished by differences in lower pI isoenzyme forms around pH 4. In the M8 strain, the epidermis, cap flesh, gill, and stalk tissue showed similar isoenzyme after isoelectric focusing, but the distribution of staining intensity appeared different for each type tissue. Younger developmental stages of M8 mushrooms showed a different isoenzyme profile than older ones. Mature mushrooms cut at the stipe showed a different distribution of isoenzyme staining than those not cut at the stipe, indicating possible activation of latent enzyme or new synthesis of specific tyrosinase isoenzymes.