During development, the inner chick retina progresses from an aerobic to an anaerobic metabolic basis because of the lack of a vascular system. To investigate this process further, we have examined the expression and distribution of mitochondrial carboxylases. Because these enzymes use covalently bound biotin as a co-enzyme, we were able to develop a new detection protocol for mitochondria usin...

In connection with studies on the /3-keto acid carboxylases of plants (1, 2), the effects of metal ions on the decarboxylation of oxalacetic acid, in the presence and absence of enzyme, were studied. In confirmation of Krebs (3) the decarboxylation was found to be accelerated by a variety of polyvalent cations. It was also observed that the enzyme oxalacetic carboxylase from parsley roots, whic...

In two previous reports, it was shown that cocarboxylase and p-aminobenzoic acid counteract the inhibitory effect of sulfathiazole on yeast and bacterial carboxylases. Whereas cocarboxylase brings about this effect without exercising any inhibitory action on carboxylase, p-aminobenzoic acid exercises the antagonistic action to sulfathiazole while maintaining a certain degree of inhibitory effec...

Analysis of a region of chromosomal DNA lying between jadR1 and jadI in the gene cluster for jadomycin biosynthesis in Streptomyces venezuelae ISP5230 detected an ORF encoding 584 amino acids similar in sequence to the biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) components of acyl-coenzyme A carboxylases. Multiple sequence alignments of the deduced Jad protein with acyl-c...

In Mycobacterium tuberculosis, the carboxylation of acetyl coenzyme A (acetyl-CoA) to produce malonyl-CoA, a building block in long-chain fatty acid biosynthesis, is catalyzed by two enzymes working sequentially: a biotin carboxylase (AccA) and a carboxyltransferase (AccD). While the exact roles of the three different biotin carboxylases (AccA1 to -3) and the six carboxyltransferases (AccD1 to ...

Biotin is an essential cofactor of cell metabolism serving as a protein-bound coenzyme in ATP-dependent carboxylation, in transcarboxylation, and certain decarboxylation reactions. The involvement of biotinylated proteins in other cellular functions has been suggested occasionally, but available data on this are limited. In the present study, a Saccharomyces cerevisiae protein was identified th...

Woronick and Johnson (1) observed in Aspergillus niger extracts a pyruvate carboxylating system requiring adenosine triphosphate, but not involving phosphopyruvate, and suggested that the carboxylation reaction was coupled with the conversion of adenosine triphosphate to adenosine diphosphate and inorganic phosphate. Utter and Keech (2) studied a similar reaction in extracts of avian and beef l...

The posttranslational gamma-carboxylation of glutamate residues in secreted proteins to gamma-carboxyglutamate is carried out by the vitamin K-dependent enzyme gamma-glutamyl carboxylase. gamma-Carboxylation has long been thought to be a biochemical specialization of vertebrates, essential for blood clotting. Recently, a gamma-carboxylase was shown to be expressed in Drosophila, although its fu...

We describe a 3-year-old boy with biotin dependency not caused by biotinidase, holocarboxylase synthetase, or nutritional biotin deficiency. We sought to define the mechanism of his biotin dependency. The child became acutely encephalopathic at age 18 months. Urinary organic acids indicated deficiency of several biotin-dependent carboxylases. Symptoms improved rapidly following biotin supplemen...