Work

Prosegment of Tripeptidyl Peptidase I Is a Potent, Slow-binding Inhibitor of Its Cognate Enzyme

Year: 2008

Type: article

Abstract: Tripeptidyl peptidase I (TPP I) is the first mammalian representative of a family of pepstatin-insensitive serine-carboxyl proteases, or sedolisins. The enzyme acts in lysosomes, where it sequentially removes tripeptides from the unmodified N terminus of small, unstructured polypeptides. Naturally occurring mutations in TPP I underlie a neurodegenerative disorder of childhood, classic late infantile neuronal ceroid lipofuscinosis (CLN2). Generation of mature TPP I is associated with removal of a long prosegment of 176 amino acid residues from the zymogen. Here we investigated the inhibitory properties of TPP I prosegment expressed and isolated from Escherichia coli toward its cognate protease. We show that the TPP I prosegment is a potent, slow-binding inhibitor of its parent enzyme, with an overall inhibition constant in the low nanomolar range. We also demonstrate the protective effect of the prosegment on alkaline pH-induced inactivation of the enzyme. Interestingly, the inhibitory properties of TPP I prosegment with the introduced classic late infantile neuronal ceroid lipofuscinosis disease-associated mutation, G77R, significantly differed from those revealed by wild-type prosegment in both the mechanism of interaction and the inhibitory rate. This is the first characterization of the inhibitory action of the sedolisin prosegment.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m800458200

Authors: Adam A. Golabek, Natalia Dolzhanskaya, Marius Walus, Krystyna E. Wisniewski, Elizabeth Kida

Language: English

Topic: Lysosomal Storage Disorders Research

Subfield: Genetics (clinical)

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430

Funders: National Institutes of Health, National Institute of Neurological Disorders and Stroke