Purification, Characterization, and Localization of Aspartoacylase from Bovine Brain

Rajinder Kaul, Jose Casanova, Anne B. Johnson, Peter Tang, Reuben Matalon

Research output: Contribution to journalArticle

91 Scopus citations

Abstract

Abstract: Canavan disease, an autosomal recessive disorder, is characterized biochemically by N‐acetylaspartic aciduria and aspartoacylase (N‐acyl‐L‐aspartate amidohydrolase; EC 3.5.1.15) deficiency. However, the role of aspartoacylase and N‐acetylaspartic acid in brain metabolism is unknown. Aspartoacylase has been purified to apparent homogeneity with a specific activity of ∼ 19,000–20,000 nmol of aspartate released/mg of protein. The native enzyme is a 58‐kDa monomer. The purified aspartoacylase activity is enhanced by divalent cations, nonionic detergents, and dithiothreitol. Low levels of dithiothreitol or β‐mercaptoethanol are required for enzyme stability. Aspartoacylase has a Km of 8.5 × 10−4M and a Vmax of 43,000 nmol/min/mg of protein. Inhibition of aspartoacylase by glycyl‐L‐aspartate and amino derivatives of D‐aspartic acid suggests that the carbon backbone of the substrate is primarily involved in its interaction with the active site and that a blocked amino group is essential for the catalytic activity of aspartoacylase. Biochemical and immunocytochemical studies revealed that aspartoacylase is localized to white matter, whereas the N‐acetylaspartic acid concentration is threefold higher in gray matter than in white matter. Our studies so far indicate that aspartoacylase is conserved across species during evolution and suggest a significant role for aspartoacylase and N‐acetylaspartic acid in normal brain biology.

Original languageEnglish (US)
Pages (from-to)129-135
Number of pages7
JournalJournal of neurochemistry
Volume56
Issue number1
DOIs
StatePublished - Jan 1991
Externally publishedYes

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Keywords

  • Aminoacylase II
  • Canavan disease
  • Myelin
  • N‐Acetylaspartic acid
  • Spongy degeneration

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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