{"id":{"repo_id":"wvu","oai_identifier":"oai:researchrepository.wvu.edu:etd-2573"},"canonical_url":"https://search.dev.ndltd.org/etd/wvu/oai:researchrepository.wvu.edu:etd-2573","repository":{"repo_id":"wvu","name":"West Virginia University","base_url":"https://researchrepository.wvu.edu/do/oai/"},"display":{"title":"Thermodynamic effects of phospholamban on Ca-ATPase kinetics","abstract":"The Ca-ATPase of sarcoplasmic reticulum removes cytosolic calcium to promote muscle relaxation. In the heart, the Ca-ATPase is regulated by phospholamban, which inhibits the Ca-ATPase by decreasing Ca-ATPase calcium sensitivity. However, the kinetic and thermodynamic mechanisms of inhibition are not understood. The purpose of this research was to test the hypothesis that phospholamban regulates Ca-ATPase kinetics by increasing Ca-ATPase activation energy. The baculovirus-insect cell expression system was used to produce samples containing Ca-ATPase alone or Ca-ATPase with phospholamban. The temperature-dependence of Ca-ATPase activity and catalytic site density was measured in the absence and presence of phospholamban at sub-saturating calcium and used to calculate the temperature-dependence of Ca-ATPase turnover. Arrhenius analyses showed that phospholamban increased Ca-ATPase activation energy from 31 +/- 3 J/mol (Ca-ATPase only) to 52 +/- 5 J/mol (Ca-ATPase + phospholamban). The results supported the hypothesis and provided new insight into the mechanism of phospholamban inhibition of Ca-ATPase.","abstract_html":"The Ca-ATPase of sarcoplasmic reticulum removes cytosolic calcium to promote muscle relaxation. In the heart, the Ca-ATPase is regulated by phospholamban, which inhibits the Ca-ATPase by decreasing Ca-ATPase calcium sensitivity. However, the kinetic and thermodynamic mechanisms of inhibition are not understood. The purpose of this research was to test the hypothesis that phospholamban regulates Ca-ATPase kinetics by increasing Ca-ATPase activation energy. The baculovirus-insect cell expression system was used to produce samples containing Ca-ATPase alone or Ca-ATPase with phospholamban. The temperature-dependence of Ca-ATPase activity and catalytic site density was measured in the absence and presence of phospholamban at sub-saturating calcium and used to calculate the temperature-dependence of Ca-ATPase turnover. Arrhenius analyses showed that phospholamban increased Ca-ATPase activation energy from 31 +/- 3 J/mol (Ca-ATPase only) to 52 +/- 5 J/mol (Ca-ATPase + phospholamban). The results supported the hypothesis and provided new insight into the mechanism of phospholamban inhibition of Ca-ATPase.","abstract_has_math":false,"creators":["Apopa, Patrick L."],"institution":null,"degree_name":"MS","degree_level":"Thesis","degree_discipline":"Biochemistry","degree_department":null,"school":null,"contributors":["Jim Mahaney."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-12-01T08:00:00Z","date_published":"2002-12-01T08:00:00Z","updated_at":"2026-07-24T06:15:55Z","subjects":["Biochemistry"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://researchrepository.wvu.edu/etd/1570"],"render_values":[{"text":"https://researchrepository.wvu.edu/etd/1570","href":"https://researchrepository.wvu.edu/etd/1570","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.33915/etd.1570","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jim Mahaney."]},{"key":"dc:creator","label":"Author","values":["Apopa, Patrick L."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2019-01-17T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biochemistry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["MS"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biochemistry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.33915/etd.1570","https://researchrepository.wvu.edu/etd/1570"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The Ca-ATPase of sarcoplasmic reticulum removes cytosolic calcium to promote muscle relaxation. In the heart, the Ca-ATPase is regulated by phospholamban, which inhibits the Ca-ATPase by decreasing Ca-ATPase calcium sensitivity. However, the kinetic and thermodynamic mechanisms of inhibition are not understood. The purpose of this research was to test the hypothesis that phospholamban regulates Ca-ATPase kinetics by increasing Ca-ATPase activation energy. The baculovirus-insect cell expression system was used to produce samples containing Ca-ATPase alone or Ca-ATPase with phospholamban. The temperature-dependence of Ca-ATPase activity and catalytic site density was measured in the absence and presence of phospholamban at sub-saturating calcium and used to calculate the temperature-dependence of Ca-ATPase turnover. Arrhenius analyses showed that phospholamban increased Ca-ATPase activation energy from 31 +/- 3 J/mol (Ca-ATPase only) to 52 +/- 5 J/mol (Ca-ATPase + phospholamban). The results supported the hypothesis and provided new insight into the mechanism of phospholamban inhibition of Ca-ATPase."]},{"key":"dc:title","label":"Title","values":["Thermodynamic effects of phospholamban on Ca-ATPase kinetics"]}]}],"canonical_facts":{"dc:contributor":["Jim Mahaney."],"dc:creator":["Apopa, Patrick L."],"dc:date.available":["2019-01-17T08:00:00Z"],"dc:description.abstract":["The Ca-ATPase of sarcoplasmic reticulum removes cytosolic calcium to promote muscle relaxation. In the heart, the Ca-ATPase is regulated by phospholamban, which inhibits the Ca-ATPase by decreasing Ca-ATPase calcium sensitivity. However, the kinetic and thermodynamic mechanisms of inhibition are not understood. The purpose of this research was to test the hypothesis that phospholamban regulates Ca-ATPase kinetics by increasing Ca-ATPase activation energy. The baculovirus-insect cell expression system was used to produce samples containing Ca-ATPase alone or Ca-ATPase with phospholamban. The temperature-dependence of Ca-ATPase activity and catalytic site density was measured in the absence and presence of phospholamban at sub-saturating calcium and used to calculate the temperature-dependence of Ca-ATPase turnover. Arrhenius analyses showed that phospholamban increased Ca-ATPase activation energy from 31 +/- 3 J/mol (Ca-ATPase only) to 52 +/- 5 J/mol (Ca-ATPase + phospholamban). The results supported the hypothesis and provided new insight into the mechanism of phospholamban inhibition of Ca-ATPase."],"dc:identifier":["https://doi.org/10.33915/etd.1570","https://researchrepository.wvu.edu/etd/1570"],"dc:subject":["Biochemistry"],"dc:title":["Thermodynamic effects of phospholamban on Ca-ATPase kinetics"],"thesis:degree_discipline":["Biochemistry"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["MS"]},"updated_at":"2026-07-24T06:15:55Z"}