NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999.

  • By agreement with the publisher, this book is accessible by the search feature, but cannot be browsed.
Cover of Basic Neurochemistry

Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition.

Show details

Chapter 44Diseases of Amino Acid Metabolism

.

Author Information
Figure 44-1. Major pathways of branched-chain amino acid metabolism.

Figure 44-1

Major pathways of branched-chain amino acid metabolism. Maple syrup urine disease is caused by a congenital deficiency of reaction 2. Many of the primary organic acidurias, for example, isovaleric acidemia and methylmalonic acidemia, are referable to (more...)

Figure 44-3. Catabolism of lysine, hydroxylysine and tryptophan.

Figure 44-3

Catabolism of lysine, hydroxylysine and tryptophan. Glutaric aciduria is caused by a congenital absence of glutaryl-CoA dehydrogenase (reaction 3). Enzymes: 1, lysine-ketoglutarate dehydrogenase; 2, NAD-dependent dehydrogenase; 3, glutaryl-CoA dehydrogenase; (more...)

Figure 44-4. The phenylalanine hydroxylase (PAH) pathway.

Figure 44-4

The phenylalanine hydroxylase (PAH) pathway. Phenylketonuria usually is caused by a congenital deficiency of PAH (reaction 1), but it also can result from defects in the metabolism of biopterin, which is a cofactor for the hydroxylase. Enzymes: 1, phenylalanine (more...)

Figure 44-5. Glycine-cleavage system and some related reactions.

Figure 44-5

Glycine-cleavage system and some related reactions. Glycine and serine are readily interchangeable. Enzymes: 1, glycine-cleavage system; 2, and 4, serine hydroxymethyltransferase; 3, N5,10-methylenetetrahydrolate reductase. N5,10CH2-FH4, N5,10-methylenetetrahydrolate; (more...)

Figure 44-2. The trans-sulfuration pathway and related metabolic routes.

Figure 44-2

The trans-sulfuration pathway and related metabolic routes. Homocystinuria usually is caused by a congenital deficiency of cystathionine β-synthase (reaction 5). Sometimes homocystinuria is caused by a failure of the remethylation of homocysteine. (more...)

Figure 44-6. The urea cycle and related reactions of ammonia metabolism.

Figure 44-6

The urea cycle and related reactions of ammonia metabolism. Congenital hyperammonemia syndromes usually are caused by a deficiency of one of the enzymes of the urea cycle. Ammonia also can be metabolized to glutamate, alanine, glutamine and glycine. Administration (more...)

Figure 44-7. Metabolism of glutathione.

Figure 44-7

Metabolism of glutathione. Deficiency in reaction 2 leads to severe metabolic acidosis caused by excessive formation of 5-oxoproline from γ-glutamylcysteine in reaction 4. Deficiencies in reactions 1 and 3 also have neurological effects. Deficiencies (more...)

Aminoacidopathies involve an inherited deficiency of an enzyme or transport system that mediates the metabolism of a particular amino acid (Table 44-1). As a result, the amino acid accumulates and evokes a toxicity syndrome that commonly extends to the CNS. The severity of the clinical picture depends on the amino acid involved, the duration of its accumulation and the supervention of other medical complications, for example, hypoglycemia [1,2].

Table 44-1. Disorders of Amino Acid Metabolisma.

Table 44-1

Disorders of Amino Acid Metabolisma.

Neurochemists have long been interested in the relationship between the biochemical derangement and brain injury since careful scrutiny of the latter may reveal the significance of the involved metabolic pathway to normal function. These relationships are still poorly understood for most amino acidurias.

  • Biochemistry of Amino Acid Disorders
  • Pathogenesis of Clinical Features
  • Branched-Chain Amino Acid Metabolism
  • Disorders of Organic Acid Metabolism
  • Organic Acid Metabolism
  • Phenylalanine Metabolism: Phenylketonuria
  • Glycine Metabolism: Nonketotic Hyperglycinemia
  • Sulfur Amino Acid Metabolism: Homocystinuria
  • Urea Cycle
  • Biotin Metabolism
  • Glutathione Metabolism
  • GABA Metabolism
  • N-Acetylaspartate Metabolism: Canavan's Disease
  • References

By agreement with the publisher, this book is accessible by the search feature, but cannot be browsed.

Copyright © 1999, American Society for Neurochemistry.
Bookshelf ID: NBK20436

Views

  • Cite this Page
  • Disable Glossary Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...