Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Life Sciences
Investigating And Modeling Possible Mechanisms By Which Healthy Cell Membranes Become Resistant To Hydrolysis By Secretory Phospholipase A2, Jennifer Nelson
Investigating And Modeling Possible Mechanisms By Which Healthy Cell Membranes Become Resistant To Hydrolysis By Secretory Phospholipase A2, Jennifer Nelson
Theses and Dissertations
Secretory phospholipase A2 (sPLA2) behaves differently toward the membranes of healthy cells compared to those of damaged or dying cells. The enzyme catalyzes rapid and sustained hydrolysis of compromised cells consistent with a simple catalytic mechanism. In contrast, when healthy cells are incubated with sPLA2, they become resistant to hydrolytic attack as manifest by three unusual observations: First, hydrolysis is transient and represents only a small fraction of the total membrane phospholipid content. Second, subsequent addition of sPLA2 fails to generate additional product. Third, the apparent potency of the enzyme to cause the membrane to be refractory is much greater …
Mechanisms By Which Apoptotic Membranes Become Susceptible To Secretory Phospholipase A2, Rachel Williams Bailey
Mechanisms By Which Apoptotic Membranes Become Susceptible To Secretory Phospholipase A2, Rachel Williams Bailey
Theses and Dissertations
During apoptosis, changes occur in T-lymphocyte membranes that render them susceptible to hydrolysis by secretory phospholipase A2 (sPLA2). To study the relevant mechanisms, a simplified model of apoptosis using a calcium ionophore was first applied. Kinetic and flow cytometry experiments provided key observations regarding ionophore treatment: initial hydrolysis rate was elevated, total reaction product was increased four-fold, and adsorption of the enzyme to the membrane surface was unaltered. Analysis of these results suggested that susceptibility during calcium-induced apoptosis is limited by substrate availability rather than enzyme adsorption. Fluorescence experiments identified three membrane alterations that might affect substrate access to the …