Ornithine aminotransferase
Encyclopedia
Ornithine aminotransferase is an enzyme
involved in the ultimate formation of proline
from ornithine
. Ornithine aminotransferase forms the initial intermediate in this process. It catalyzes the reverse reaction as well, and is therefore essential in creating ornithine from the starting substrate proline. Glutamate acts as the amine donor for ornithine aminotransferase, forming α-ketoglutarate. In the reverse direction, α-ketoglutarate accepts the amine group, forming glutamate and leading to the ultimate conversion of proline
to ornithine
.
Ornithine aminotransferase catalyzes the following reaction:
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
involved in the ultimate formation of proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...
from ornithine
Ornithine
Ornithine is an amino acid that plays a role in the urea cycle.-Role in urea cycle:L-Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen....
. Ornithine aminotransferase forms the initial intermediate in this process. It catalyzes the reverse reaction as well, and is therefore essential in creating ornithine from the starting substrate proline. Glutamate acts as the amine donor for ornithine aminotransferase, forming α-ketoglutarate. In the reverse direction, α-ketoglutarate accepts the amine group, forming glutamate and leading to the ultimate conversion of proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...
to ornithine
Ornithine
Ornithine is an amino acid that plays a role in the urea cycle.-Role in urea cycle:L-Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen....
.
Ornithine aminotransferase catalyzes the following reaction:
- L-ornithine + a 2-oxo acid = L-glutamate 5-semialdehyde + an L-amino acid