Publications

• Specificity of amino acid acylases.

  BIRNBAUM S.M., LEVINTOW L., KINGSLEY R.B., GREENSTEIN J.P.

  J Biol Chem 194:455-470(1952) [PubMed] [EuropePMC]

• Clinically distinct phenotypes of Canavan disease correlate with residual aspartoacylase enzyme activity.

  Mendes M.I., Smith D.E., Pop A., Lennertz P., Fernandez Ojeda M.R., Kanhai W.A., van Dooren S.J., Anikster Y., Baric I., Boelen C., Campistol J., de Boer L., Kariminejad A., Kayserili H., Roubertie A., Verbruggen K.T., Vianey-Saban C., Williams M., Salomons G.S.

  We describe 14 patients with 12 novel missense mutations in ASPA, the gene causing Canavan disease (CD). We developed a method to study the effect of these 12 variants on the function of aspartoacylase-the hydrolysis of N-acetyl-l-aspartic acid (NAA) to aspartate and acetate. The wild-type ASPA op ... >> More

  We describe 14 patients with 12 novel missense mutations in ASPA, the gene causing Canavan disease (CD). We developed a method to study the effect of these 12 variants on the function of aspartoacylase-the hydrolysis of N-acetyl-l-aspartic acid (NAA) to aspartate and acetate. The wild-type ASPA open reading frame (ORF) and the ORFs containing each of the variants were transfected into HEK293 cells. Enzyme activity was determined by incubating cell lysates with NAA and measuring the released aspartic acid by LC-MS/MS. Clinical data were obtained for 11 patients by means of questionnaires. Four patients presented with a non-typical clinical picture or with the milder form of CD, whereas seven presented with severe CD. The mutations found in the mild patients corresponded to the variants with the highest residual enzyme activities, suggesting that this assay can help evaluate unknown variants found in patients with atypical presentation. We have detected a correlation between clinical presentation, enzyme activity, and genotype for CD. << Less

  Hum. Mutat. 38:524-531(2017) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Identification of the zinc binding ligands and the catalytic residue in human aspartoacylase, an enzyme involved in Canavan disease.

  Herga S., Berrin J.G., Perrier J., Puigserver A., Giardina T.

  Canavan disease is an autosomal-recessive neurodegenerative disorder caused by a lack of aspartoacylase, the enzyme that degrades N-acetylaspartate (NAA) into acetate and aspartate. With a view to studying the mechanisms underlying the action of human aspartoacylase (hASP), this enzyme was express ... >> More

  Canavan disease is an autosomal-recessive neurodegenerative disorder caused by a lack of aspartoacylase, the enzyme that degrades N-acetylaspartate (NAA) into acetate and aspartate. With a view to studying the mechanisms underlying the action of human aspartoacylase (hASP), this enzyme was expressed in a heterologous Escherichia coli system and characterized. The recombinant protein was found to have a molecular weight of 36 kDa and kinetic constants K(m) and k(cat) of 0.20 +/- 0.03 mM and 14.22 +/-0.48 s(-1), respectively. Sequence alignment showed that this enzyme belongs to the carboxypeptidase metalloprotein family having the conserved motif H(21)xxE(24)(91aa)H(116). We further investigated the active site of hASP by performing modelling studies and site-directed mutagenesis. His21, Glu24 and His116 were identified here for the first time as the residues involved in the zinc-binding process. In addition, mutations involving the Glu178Gln and Glu178Asp residues resulted in the loss of enzyme activity. The finding that wild-type and Glu178Asp have the same K(m) but different k(cat) values confirms the idea that the carboxylate group contributes importantly to the enzymatic activity of aspartoacylase. << Less

  FEBS Lett. 580:5899-5904(2006) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Aspartoacylase is a regulated nuclear-cytoplasmic enzyme.

  Hershfield J.R., Madhavarao C.N., Moffett J.R., Benjamins J.A., Garbern J.Y., Namboodiri A.

  Mutations in the gene for aspartoacylase (ASPA), which catalyzes deacetylation of N-acetyl-L-aspartate in the central nervous system (CNS), result in Canavan Disease, a fatal dysmyelinating disease. Consistent with its role in supplying acetate for myelin lipid synthesis, ASPA is thought to be cyt ... >> More

  Mutations in the gene for aspartoacylase (ASPA), which catalyzes deacetylation of N-acetyl-L-aspartate in the central nervous system (CNS), result in Canavan Disease, a fatal dysmyelinating disease. Consistent with its role in supplying acetate for myelin lipid synthesis, ASPA is thought to be cytoplasmic. Here we describe the occurrence of ASPA within nuclei of rat brain and kidney, and in cultured rodent oligodendrocytes. Immunohistochemistry showed cytoplasmic and nuclear ASPA staining, the specificity of which was demonstrated by its absence from tissues of the Tremor rat, an ASPA-null mutant. Subcellular fractionation analysis revealed low enzyme activity against NAA in nuclear fractions from normal rats. Whereas two recent reports have indicated that ASPA exists as a dimer, size-exclusion chromatography of subcellular fractions showed ASPA is an active monomer in both subcellular fractions. Western blotting detected ASPA as a single 38 kD band. Because ASPA is small enough to passively diffuse into the nucleus, we constructed, expressed, and detected in COS-7 cells a green fluorescent protein-human ASPA (GFP-hASPA) fusion protein larger than the permissible size for the nuclear pore complex. GFP-hASPA was enzymatically active and showed mixed nuclear-cytoplasmic distribution. We conclude that ASPA is a regulated nuclear-cytoplasmic protein that may have distinct functional roles in the two cellular compartments. << Less

  FASEB J. 20:2139-2141(2006) [PubMed] [EuropePMC]

• New T530C mutation in the aspartoacylase gene caused Canavan disease with no correlation between severity and N-acetylaspartate excretion.

  Di Pietro V., Cavallari U., Amorini A.M., Lazzarino G., Longo S., Poggiani C., Cavalli P., Tavazzi B.

  <h4>Objective</h4>Canavan disease (OMIM 271900) is a severe autosomal recessive neurodegenerative disorder characterized by spongy degeneration of the brain and caused by mutations in the gene encoding for aspartoacylase (ASPA). The enzyme is responsible for the catalyses of the brain-specific com ... >> More

  <h4>Objective</h4>Canavan disease (OMIM 271900) is a severe autosomal recessive neurodegenerative disorder characterized by spongy degeneration of the brain and caused by mutations in the gene encoding for aspartoacylase (ASPA). The enzyme is responsible for the catalyses of the brain-specific compound N-acetylaspartate (NAA).<h4>Design and methods</h4>We report the case of two Egyptian sibling patients suspected of Canavan disease (CD) showing clinical deterioration, white matter degeneration, megalencephaly and severe intellectual impairment. The patients underwent magnetic resonance imaging (MRI) and biochemical analysis of NAA in biological fluid samples (serum and urine). Subsequently, in order to determine the mutation responsible for CD in these two sibs, a molecular biological examination was performed.<h4>Results</h4>MRI findings and quantification of high NAA excretion (1378.5 and 680.1μmolNAA/mmolcreatinine in urine of 4months and 4years old patients, respectively) confirmed the diagnosis of CD and prompted a search for the responsible mutation. The molecular biological analysis revealed homozygosity for the substitution T530C (Ile177Thr) in the exon 4 of the ASPA gene in both sibs. A total loss of enzymatic activity was also recorded.<h4>Conclusions</h4>The substitution T530C (Ile177Thr) results in a novel missense mutation causing a CD phenotype with severe clinical characteristics. This mutation was not previously described in the literature. In these two sibs, urinary concentration of NAA appears to correlate inversely to symptom severity and CD progression. << Less

  Clin. Biochem. 46:1902-1904(2013) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.