β-Glucuronidase as an index of growth in the uterus and other organs

Abstract

1.The component of crude mushroom extracts which is responsible for the appearance of a purple colour when such extracts oxidize catechol has been identified by isolation of L-proline.2. Thepigment-formingreactionhasbeenstudied in respect of coleur intensity developed, oxygen absorbed and hydrogen ion liberated, in systems containing purified tyrosinase, catechol or homo- catechol, and one of the following: proline, hydroxyproline, hydroxyproline ethyl ester, pyrrolidine, glycine, dimethylamine and methylamine.A few experiments were also carried out with alanine, glutamic acid and arginine.The same intense purple colour was obtained in each case in which the nitrogenous substance present had a secondary amino group; the compounds with primary amino nitrogen gave a much less intense orange-red colour.3. From homocatechol and hydroxyproline ethyl ester, by oxidation with silver oxide in ethanol, 4- (4'-hydroxy-2'-carbethoxy-1'-pyrrolidyl)-5-methylo-benzoquinone has been prepared in a pure state.It appears to be identical with the pigment formed from the same precursors in the enzymic reaction mixture, and it is concluded that all the pigments have an analogous structure, and that the pigmentforming reaction is essentially a condensation be- tween 1 mol. of o-quinone and 1 mol. of nitrogenous base to give a leuco pigment which is spontaneously oxidized to the coloured form by oxygen.4. In the case of glycine, when this is present in excess, the formation of pigment is followed by oxidation of the excess amino-acid, with liberation of ammonia.Further oxidation of this type does not take place in the case of the imino acid pigments.