A kinetic model describing melanin formation by means of mushroom tyrosinase
A kinetic model describing melanin formation by means of mushroom tyrosinase
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DOI：
10.1016/j.foodres.2009.08.013
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发表时间：
2010-01-01
影响因子：
8.1
通讯作者：
Ibarz, Albert
中科院分区：
文献类型：
--
作者：
Falguera, Victor;Pagan, Jordi;Ibarz, Albert
黑色素是在含有酚类或多酚分子的植物组织中通过酶反应形成的一组多相聚合物。最近的研究发现，黑色素具有抗氧化、抗炎、免疫和抗肿瘤等有益健康的特性，因此不仅应该重新考虑它的消除，而且可以建议将它添加到新创造的功能食品中。然后，在其可能的工业应用之前，需要对黑素生成的动力学机制有进一步的了解。本文建立了用蘑菇酪氨酸酶催化L酪氨酸生成黑色素的自催化动力学模型，并测定了溶液的吸光度，并与实验数据进行了拟合。这个表达式允许将黑色素的形成描述为反应时间的函数，包括一些重要的参数，如消光系数。在产生无色中间体的滞后期后，吸光度将开始增长。产生的产物的消光系数不是一个恒定值，因为它取决于每个实验的条件。酪氨酸酶对L酪氨酸的催化作用似乎低于对L多巴的催化作用。(C)2009爱思唯尔有限公司。保留所有权利。
Melanins are an heterogeneous group of polymers formed by enzymatic reactions in vegetable tissues containing phenolic or polyphenolic molecules. Recent studies have discovered some beneficial properties of melanins on health, such as anti-oxidative, anti-inflammatory, immune and anti-tumor properties, so not only its elimination should be reconsidered, but also its addition could be proposed to functional food of new creation. Then, a further knowledge about the kinetic mechanism of melanogenesis is required prior to its possible industrial utilization. In this work, an autocatalytic kinetic model to explain melanin formation from L-tyrosine using mushroom tyrosinase and measuring the absorbance of the solution has been developed and fitted to experimental data. This expression allows to describe melanin formation as a function of time of reaction, including some important parameters such as the extinction coefficient. Absorbance will start growing after a lag period in which colorless intermediates are produced. The extinction coefficient of the resulting products is not a constant value, because it depends on the conditions of each experiment. Tyrosinase seemed to have a lower catalytic effect on L-tyrosine than on L-DOPA. (C) 2009 Elsevier Ltd. All rights reserved.