Even though intervertebral disc degeneration can be found in the natural course of alkaptonuria, detection of the disease by black disc color change in a patient without any other presentation of alkaptonuria is an exceptionally rare condition. We have reported a very rare case of alkaptonuria presented with low back pain and steppage gait in a 51-year-old male with a complaint of chronic low-b...

Recently considerable work has been reported on the enzyme system in mammalian liver which metabolizes tyrosine to fumarate and acetoacetate. This conversion has been shown to consist of several steps, involving first a transamination of tyrosine to p-hydroxyphenylpyruvic acid, and subsequent oxidation of this intermediate to 2,5-dihydroxyphenylpyruvic acid, then to homogentisic acid, and final...

Dothideaceous black yeast-like fungi (BYF) are known to synthesise DHN-melanin that is inhibited by the systemic fungicide tricyclazole. The final step of the DHN melanin pathway is the conjoining of 1,8-DHN molecules to form the melanin polymer. There are several candidate enzymes for this step, including phenoloxidases such as tyrosinase and laccases, peroxidases, and perhaps also catalases. ...

volume 34. Another feature which had been extended to this volume is a cumulative index for all four volumes of the series. The preparations of compounds described in the present volume include: galactose-l-phosphate, homogentisic acid, dipalmitoyl-lecithin, lactalbumin, lactoglobulin, carnosine, histidinol dihydrochloride, urocanic acid, Nacetylimidazole, glycolaldehyde, sodium glyoxylate, glu...

Alkaptonuria is a rare inherited genetic disorder of tyrosine metabolism that causes the urine to turn black on contact with the air when homogentisic acid is oxidized to form a pigment-like polymer material [1,2]. The earliest sign of the disorder is the tendency for babies’ diapers to stain black; later on in childhood and early adulthood, there is an asymptomatic, progressive deposition of t...

DeniLite laccase immobilized platinum electrode was used for amperometric detection of hydroquinone (HQ) and homogentisic acid (HGA) by means of substrate recycling. In case of HQ, the obtained sensitivity is 280 nA/μM with linear range of 0.2-35 μM (r = 0.998) and detection limit (S/N = 3) of 50 nM. This high sensitivity can be attributed to chemical amplification due to the cycling of the sub...