SPECIFICITY OF PROPEPTIDE CONVERTING ENZYMES

Project: Research project

Project Details

Description

DESCRIPTION: This proposal focuses on using proinsulin as a model substrate
to address two fundamental questions regarding peptide-converting enzymes
(PCE)-mediated processing. First, is the processing specificity determined
by structural elements within the PCEs? Second, what specific structural
elements of the PCEs are involved in the precise recognition of propeptide
cleavage sites?

The inial goal of this project is to obtain sufficient proinsulin for use in
an in vitro enzyme assay. Products of the in vitro assay will be subjected
to structural characterization to conclusively define the sites of
PCE-mediated cleavage. This assay will then be used to test the effects of
microdomain swapping between PC1 and PC2 in an attempt to define which
structural regions of an individual furin/PC member is responsible for
substrate recognition. Finally the proinsulin substrate will be manipulated
to determine whether its three dimensional structure affects processing
specificity. Results from these studies should provide valuable information
regarding the tertiary structural interactions between the PCEs and their
propeptide substrates.

A number of cases of hyperproinsulinemia, hyperproglucanemia, insulin
resistance and at least two cases of hemophilia have been shown to be caused
by mutations affecting the endoproteolytic cleavage site in propeptides.
These observations raise the possibility that patients could be treated by
administering a modified version of the PCE via gene therapy.
StatusNot started