• Title/Summary/Keyword: three tyrosinase isozymes

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Analysis on Enzymatic Browning in Pine Needles (솔잎에서 발생하는 효소학적 갈변작용에 관한 분석)

  • Kong, Kwang-Hoon;Park, Hee-Joong;Choi, Sang-Sook;Cho, Sung-Hye;Kim, Yong-Tae
    • Analytical Science and Technology
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    • v.12 no.3
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    • pp.256-259
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    • 1999
  • Tyrosinases are related to the enzymatic browning of plants and attract the major scientific interest for the prevention of it. Three tyrosinase isozymes ($P_1$, $P_2$ and $P_3$) from pine needles were purified to homogeneity and characterized the factors that affect their activities. The L-ascorbic acid and ${\beta}$-mercaptoethanol notably inhibited the enzymatic activities of the three isozymes. The sodium diethyldithiocarbamate was a competitive inhibitor of isozymes with the $K_i$ values of $P_1$(0.030 mM), $P_2$(0.015 mM) and $P_3$(0.019 mM), respectively. Their enzyme activities were however, increased by the addition of most metal ions. The optimum pH for the three isozymes was 9.0~9.5 and the optimum temperatures ranged from 55 to $60^{\circ}C$ using L-DOPA as substrate.

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