Dataset Information

Identification of proteins present in LACTB solutions overexpressed and purified from E.coli by LC-MS/MS.

ABSTRACT: Non-enzymatic D-isomerization of aspartic acid in proteins has been observed in lesions associated with age-related diseases, including cataracts and Alzheimer's disease. Since D-isomerization of Asp disrupts the physiological conformation of proteins, it has been postulated that D-isomerization of Asp in proteins is a key factor in the pathogenesis of age-related diseases. D-aspartyl endopeptidase (DAEP) activity, which cleaves proteins at the carboxy terminus of D-Asp and may induce degradation of abnormal proteins with D-isomerized Asp, has been observed in mitochondrial fractions of mammalian tissues. However, the specific proteins responsible for mammalian DAEP activity remain unknown. In this study, we identified serine beta-lactamase-like protein (LACTB) as a mammalian D-aspartyl endopeptidase. We overexpressed and purified LACTB from E. coli and found that wild-type LACTB exhibited DAEP activity, but the S164A mutant LACTB, which lacks the catalytic serine, did not. To confirm that there are no other proteins that could explain the difference in DAEP activity, we systematically identified proteins present in the purified solution of LACTB.

ORGANISM(S): Escherichia Coli

SUBMITTER: Genta Ito

PROVIDER: PXD062910 | JPOST Repository | Sat Apr 19 00:00:00 BST 2025

REPOSITORIES: jPOST

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Discovery and biochemical characterization of the D-aspartyl endopeptidase activity of the serine protease LACTB.

Ito Genta G Utsunomiya-Tate Naoko N

The Journal of biological chemistry 20250424 6

Nonenzymatic D-isomerization of aspartic acid in proteins has been observed in lesions associated with age-related diseases, including cataracts and Alzheimer's disease. Given that D-isomerization of Asp disrupts the physiological conformation of proteins, it has been postulated that D-isomerization of Asp in proteins is a key factor in the pathogenesis of age-related diseases. D-Aspartyl endopeptidase (DAEP) activity, which cleaves proteins at the carboxy terminus of D-Asp and potentially induc ...[more]

PMID: 40286848

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			Action	DRS
	20240523_SA.raw	Raw
	20240523_WT.raw	Raw
	SA_protein.xlsx	Xlsx
	WT_protein.xlsx	Xlsx