Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four types of hepatic porphyria (acute intermittent porphyria; hereditary coprophorphyria; variegate porphyria; delta-aminolevulinate dehydratase deficiency porphyria) present clinically with an identical neurological syndrome. Symptoms include severe abdominal pain, vomiting, constipation, hypertension, tachycardia, and bladder dysfunction. These symptoms have been ascribed to autonomic neuropathy. Other symptoms are motor weakness and sensory involvement, which correlate with peripheral axonal neuropathy, and mental symptoms occurring without clear morphological findings in the cerebrum. The pathogenetic mechanisms which lead to the neurological dysfunction have remained poorly understood, partly due to the lack of a suitable animal model of these rare disorders. Two hypotheses, the possible neurotoxicity of delta-aminolevulinate (ALA) and heme deficiency in nervous tissue are discussed and corresponding data from porphobilinogen-deaminase deficient mice are presented. The present evidence suggests that multiple mechanisms interact in causing the varied symptoms, including ALA interaction with GABA receptors, altered tryptophan metabolism, and possibly heme depletion in nerve cells.
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PMID:Acute porphyrias: pathogenesis of neurological manifestations. 951 77

Acute intermittent porphyria (AIP) is an autosomal-dominant disease caused by a deficiency of porphobilinogen (PBG) deaminase. Patients with AIP present with neurological syndromes such as autonomic neuropathy, peripheral axonal neuropathy or central nervous system dysfunction. We report serial MRI of a patient with AIP who had cortical and subcortical cerebral changes. A 29-year-old woman with a 6-month history of AIP had an attack with severe hyponatraemia and generalised convulsions, treated with haem arginate and supportive therapy. MRI showed central pontine and extrapontine myelinolysis and cortical laminar necrosis. These are not common in AIP, but are likely to have been caused by rapid correction of hyponatraemia and by vasospasm, which could be induced by AIP.
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PMID:Acute intermittent porphyria with central pontine myelinolysis and cortical laminar necrosis. 1060 58

Despite its growing use as a radiological indicator of neuronal viability, the biological function of N-acetylaspartate (NAA) has remained elusive. This is due in part to its unusual metabolic compartmentalization wherein the synthetic enzyme occurs in neuronal mitochondria whereas the principal metabolizing enzyme, N-acetyl-L-aspartate amidohydrolase (aspartoacylase), is located primarily in white matter elements. This study demonstrates that within white matter, aspartoacylase is an integral component of the myelin sheath where it is ideally situated to produce acetyl groups for synthesis of myelin lipids. That it functions in this manner is suggested by the fact that myelin lipids of the rat optic system are well labeled following intraocular injection of [14C-acetyl]NAA. This is attributed to uptake of radiolabeled NAA by retinal ganglion cells followed by axonal transport and transaxonal transfer of NAA into myelin, a membrane previously shown to contain many lipid synthesizing enzymes. This study identifies a group of myelin lipids that are so labeled by neuronal [14C]NAA, and demonstrates a different labeling pattern from that produced by neuronal [14C]acetate. High performance liquid chromatographic analysis of the deproteinated soluble materials from the optic system following intraocular injection of [14C]NAA revealed only the latter substance and no radiolabeled acetate, suggesting little or no hydrolysis of NAA within mature neurons of the optic system. These results suggest a rationale for the unusual compartmentalization of NAA metabolism and point to NAA as a neuronal constituent that is essential for the formation and/or maintenance of myelin. The relevance of these findings to Canavan disease is discussed.
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PMID:Intraneuronal N-acetylaspartate supplies acetyl groups for myelin lipid synthesis: evidence for myelin-associated aspartoacylase. 1152 Aug 94