Non disponible en dehors du Royaume-Uni et de l'Irlande

Application

Tyrosinase activity has been assessed in a study that developed an alternative therapeutic agent for treating hyperpigmentation. Tyrosinase has also been used in a study to investigate the oculocutaneous albinism phenotype in the Pakistani population.

Biochem/physiol Actions

Converts tyrosine to L-DOPA or tyramine to dopamine

General description

Tyrosinase is a copper-containing oxidase with activity for catechols and cresol. Tyrosinase participates in the conversion of tyrosine to dihydroxyphenylalanine (DOPA), and polymerization of DOPA leads to melanin formation. Tyrosinase has a role in browning reactions. The enzyme is said to have two binding sites for aromatic substrates and a distinct binding site for oxygen-copper.

Isoelectric point (pI): 4.7-5pH optimum is 6-7Molecular weight: 128 kDa by sedimentation velocity diffusion; 133 kDa by light-scattering measurements, and 119.5 kDa by electrophoresis.Tyrosinase is a copper-containing oxidase, which has activity for both catechols and cresol. It is responsible for browning reactions. The enzyme is reported to have two binding sites for aromatic substrates and a different binding site for oxygen-copper. The copper is probably Cu(I), with inactivation involving oxidation to Cu(II) ion.

Packaging

25000, 50000 units in glass bottle

250000, 500000, 1000000 units in poly bottle

Physical properties

Isoelectric point (pI): 4.7-5 pH optimum is 6-7 Molecular weight: 128 kDa by sedimentation velocity diffusion; 133 kDa by light-scattering measurements, and 119.5 kDa by electrophoresis.

Unit Definition

One unit = δA₂₈₀ of 0.001 per min at pH 6.5 at 25 °C in 3 mL reaction mix containing L-tyrosine.