The kynurenine pathway is a metabolic pathway

Metabolic pathway

In biochemistry, metabolic pathways are series of chemical reactions occurring within a cell. In each pathway, a principal chemical is modified by a series of chemical reactions. Enzymes catalyze these reactions, and often require dietary minerals, vitamins, and other cofactors in order to function...

 leading to the production of nicotinamide adenine dinucleotide

Nicotinamide adenine dinucleotide

Nicotinamide adenine dinucleotide, abbreviated NAD, is a coenzyme found in all living cells. The compound is a dinucleotide, since it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine base and the other nicotinamide.In metabolism, NAD is involved...

 (NAD+) from the degradation of the essential amino acid

Essential amino acid

An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism , and therefore must be supplied in the diet.-Essentiality vs. conditional essentiality in humans:...

 tryptophan

Tryptophan

Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG...

.

Kynurenine pathway and neurological diseases

The kynurenine pathway is involved in physiological functions such as behavior, sleep, thermo-regulation and pregnancy. There are also strong evidences of the kynurenine pathway involvement in neurotoxic mechanisms associated with several inflammatory neurological diseases, including AIDS dementia complex

AIDS dementia complex

AIDS dementia complex is a common neurological disorder associated with HIV infection and AIDS. It is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of brain macrophages and microglia...

, Alzheimer’s disease, Huntington’s disease, Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...

, Multiple sclerosis

Multiple sclerosis

Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

 and Parkinson's disease

Parkinson's disease

Parkinson's disease is a degenerative disorder of the central nervous system...

.