Isolation and characterization of mammalian D-aspartyl endopeptidase

• Published in: Amino acids Vol. 32; no. 1; pp. 79 - 85
• Main Authors: Kinouchi, T, Nishio, H, Nishiuchi, Y, Tsunemi, M, Takada, K, Hamamoto, T, Kagawa, Y, Fujii, N
• Format: Journal Article
• Language: English
• Published: Austria Springer Nature B.V 01-01-2007
• Subjects: Acetylcysteine - analogs & derivatives; Acetylcysteine - chemistry; Aging - metabolism; Alzheimer Disease - drug therapy; Alzheimer Disease - enzymology; Alzheimer's disease; Amino acids; Animals; Aspartic Acid Endopeptidases - antagonists & inhibitors; Aspartic Acid Endopeptidases - chemistry; Aspartic Acid Endopeptidases - isolation & purification; Caenorhabditis elegans - enzymology; Cataracts; D-Aspartic Acid - chemistry; D-Aspartic Acid - metabolism; Escherichia coli - enzymology; Glutamate Dehydrogenase - antagonists & inhibitors; Glutamate Dehydrogenase - chemistry; Glutamate Dehydrogenase - isolation & purification; Inhibitors; Life span; Mammals; Mice; Mitochondrial Membranes - enzymology; Mitochondrial Proteins - antagonists & inhibitors; Mitochondrial Proteins - chemistry; Mitochondrial Proteins - isolation & purification; Multienzyme Complexes - antagonists & inhibitors; Multienzyme Complexes - chemistry; Multienzyme Complexes - isolation & purification; Oligopeptides - chemical synthesis; Oligopeptides - chemistry; Oligopeptides - therapeutic use; Protease Inhibitors - chemical synthesis; Protease Inhibitors - chemistry; Protease Inhibitors - therapeutic use; Proteasome Endopeptidase Complex - chemistry; Proteasome Inhibitors; Proteins; Rabbits; Saccharomyces cerevisiae - enzymology; Scavengers; Succinate Dehydrogenase - antagonists & inhibitors; Succinate Dehydrogenase - chemistry; Succinate Dehydrogenase - isolation & purification
• ISSN: 0939-4451; 1438-2199
• DOI: 10.1007/s00726-006-0348-4

The accumulation of D-isomers of aspartic acid (D-Asp) in proteins during aging has been implicated in the pathogenesis of Alzheimer's disease (AD), cataracts and arteriosclerosis. Here, we identified a specific lactacystin-sensitive endopeptidase that cleaves the D-Asp-containing protein and named it D-aspartyl endopeptidase (DAEP). DAEP has a multi-complex structure (MW: 600 kDa) and is localized in the inner mitochondrial membrane. However, DAEP activity was not detected in E. coli, S. cerevisiae, and C. elegans. A specific inhibitor for DAEP, i-DAEP: (benzoyl-L-Arg-L-His-[D-Asp]-CH(2)Cl; MW: 563.01), was newly synthesized and inhibited DAEP activity (IC(50), 3 microM), a factor of ten greater than lactacystin on DAEP. On the other hand, i-DAEP did not inhibit either the 20S or 26S proteasome. And we identified succinate dehydrogenase and glutamate dehydrogenase 1 as components of DAEP by affinity label using biotinylated i-DAEP. In the long life span of mammals, DAEP may serve as a scavenger against accumulation of racemized proteins in aging. Insights into DAEP will provide the foundation for developing treatments of diseases, such as AD, in which accumulation of D-Asp-containing proteins are implicated.