关键词:
ENZYMES
摘要:
THE past twelve years have seen considerable effort A directed to the development of methods for the visualization of the distribution of hydrolytic enzymes in animal tissues. Such methods have been based on the formation of coloured pigments or dyes : (a) after or (b) during the enzymic breakdown of a suitable substrate. In the first category are methods devised by Gomori for acid1 and alkaline2 phosphatase and for phosphoamidase3, in which enzymically liberated phosphoric acid is precipitated as an insoluble salt, which is then converted into a coloured metal sulphide. Similar methods for the localization of other phosphatases have been described. Allied methods based upon enzymic liberation of fatty acids have been developed for cholinesterase5 and lipase6, which are finally made visible as coloured metal sulphides derived from a suitable salt of the *** the second category is a method originally introduced for alkaline phosphatase7, in which naphthol, enzymically liberated from its phosphate, is converted into an azo-dye by the in situ action of a diazonium salt. This process has been developed and extended by Seligman et al. for the localization of acid8 and alkaline9 phosphatase, esterase10, sul-phatase11 and glucuronidase11, as well as for the colorimetric determination of these enzymes. Critical examination12 of such methods has made it clear that the final picture obtained is governed not only by the initial distribution of the enzyme but also by many factors dependent on the complex processes employed, the properties of the enzyme and the specificity of the *** the past two years attempts have been made in this laboratory to overcome some of these factors by using substrates in which stain production spontaneously accompanies enzymie attack. The developing reagent is reduced to the simplest possible, namely, atmospheric or dissolved oxygen. Such substrates are derived from indoxyi, which exists as a tautomeric mixture of substances (I) and