HOMOGENTISIC ACID OXIDASE

Homogentisic Acid Oxidase*

In the course of a study of the properties of the homogentisic acid oxidase of rat liver the activity of other animal tissues has been briefly examined. The enzyme has been reported to occur in beef and hog (I), guinea pig (2), and rabbit (3) livers and in a strain of Pseudomonas (4). The experiments reported here show that the enzyme is also present in pigeon liver and in guinea pig, rabbit, p...

Studies on Tyrosinosis: 2, Activity of the Transaminase, Parahydroxy-phenyl-pyruvate Oxidase, and Homogentisic-acid Oxidase.

On Excretion of Homogentisic Acid

The literature on alcaptonuria has been well summarized (1--6). Paschkis et al. (7) reported that thiouracil and para-aminobenzoic acid inhibited the in vitro conversion of tyrosine to melanin by tryrosinase, and White (8) found that thiouracil inhibited melanuria. Lerner and associates (9) noted that the tyrosinase of mouse melanoma is a copper protein whose activity can be inhibited by the ad...

Determination of homogentisic acid in urine.

A relatively simple method for the quantitative determination of homogentisic acid in urine is presented. Homogentisic acid (2,5-dihydroxyphenylacetic acid) is oxidized by atmospheric oxygen in mild alkali to form 1,4-benzoquinone-2-acetic acid. The latter compound is then conjugated with 2,4-dinitrophenylhydrazine. The resulting hydrazone, in the presence of alcoholic sodium hydroxide, produce...

The enzymatic conversion of homogentisic acid to 4-fumarylacetoacetic acid.

Although the probability that homogentisic acid is an intermediate in the conversion of phenylalanine and tyrosine to acetoacetate is indicated by many experiments with humans (l-5), animals (6-9), and tissue preparations (lO-13), no direct evidence has been reported concerning the mechanism of its oxidation. However, the formation of /?-ketoadipic acid from phenol in the presence of cholera Vi...