This continuation application examines the dual proposition that two enzymatic reactions, i.e., transglutaminase-mediated cross-linking and pepstatin-inhibitable proteolysis, both of which are turned on by an elevation of intra-cellular concentration of Ca++, have profound consequences for the structural organization of membrane proteins and, hence, the physical properties of the red cell.
Specific aims relate to basic research as well as to pathological applications and are subdivided into the following categories: studies with human erythrocyte transglutaminase; compositional analysis of the Gamma-glutamyl-Epsilon-lysine cross-linked polymer formed in the membranes of Ca++ enriched cells; dynamics of forming Gamma-glutamyl-Epsilon-lysine cross-linked polymeric clusters and analysis of cross-link frequency; mode of action of pepstatin on the human red blood cell; evaluation of novel non-competitive inhibitors of red blood cell transglutaminase; differential examination of the effects of the enzymatic reactions which cause cross-linking by Gamma-glutamyl-Epsilon-lysine bridges and proteolysis in the membranes of Ca++ enriched red cells, from the point of view of irreversible fixation of echinocytic shape, permanent loss of membrane deformabiity and change in membrane density; facilitation of red cell phagocytosis by the Ca++ induced and pepstatin inhibitable degradation of band 3; measurement of the Gamma-glutamyl-Epsilon-lysine cross-link frequency in polymers obtained from the membranes of irreversibly sickled cells and evaluation of band 3 and glycophorin breakdown; transglutaminase-mediated cross-linking and pepstatin-sensitive proteolytic reactions in red cells in relation to malaria infection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK025412-13
Application #
3227395
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1979-04-01
Project End
1992-03-31
Budget Start
1991-04-01
Budget End
1992-03-31
Support Year
13
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
Schools of Arts and Sciences
DUNS #
City
Evanston
State
IL
Country
United States
Zip Code
60201