Calcium transport and ATP hydrolytic activities in guinea-pig pancreatic acinar plasma membranes
department or school: Pharmaceutical Sciences, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Mahey, Rajesh
issued: 2011-02-03T21:35:27Z
issued: 1991
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The aim of the present investigation was to determine whether a plasma membrane high affinity Ca²+-ATPase plays an integral role in the maintenance of cytoplasmic free Ca²+ in pancreatic acinar cells. To achieve this, the Ca²+-transport and Ca²+-ATPase activities were characterized and their properties compared. Plasma membranes from guinea-pig pancreatic acini were shown to contain an ATP-dependent high affinity Ca²+-pump and a high affinity Ca²+-dependent ATPase activity. In addition, a low affinity ATPase activity was also observed. The high affinity Ca²+-ATPase activity as well as the Ca²+-transport were found to be dependent on Mg²+, whereas the low affinity ATPase activity appeared to be inhibited by Mg²+. The high affinity ATPase activity was 7-fold greater in magnitude than the Ca²+-transport. Whereas the Ca²+-transport was very specific for ATP as a substrate, the high affinity Ca²+-ATPase showed little specificity for various nucleotide triphosphates. These data would suggest that the Ca²+-transport and the high affinity Ca²+-dependent ATPase in guinea-pig pancreatic acinar plasma membranes may be two distinct activities To further investigate whether the two activities were related, we investigated how the Ca²+-transport and Ca²+-ATPase activities were regulated by intracellular mediators. Regulation of the two activities by calmodulin, cyclic AMP-dependent protein kinase, Protein kinase C and inositol phosphates was investigated. Calmodulin failed to stimulate either activity. In addition, calmodulin antagonists, trifluoperazine and compound 48/80 produced a concentration-dependent inhibition of Ca²+-transport. These data suggested the presence of endogenous calmodulin. Both antagonists failed to influence the Ca²+-dependent ATPase activity. Experiments using boiled extracts from guinea-pig pancreatic acinar plasma membranes and erythrocyte plasma membranes Ca²+-ATPase confirmed the presence of endogenous calmodulin. The catalytic subunit of cyclic AMP-d…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/31044
note: CALCIUM TRANSPORT AND ATP HYDROLYTIC ACTIVITIES IN GUINEA-PIG PANCREATIC ACINAR PLASMA MEMBRANES by RAJESH MAHEY B.Sc. (Hon.), Sunderland Polytechnic, England, 1983 M.Sc, University of British Columbia, Canada, 1987 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy in THE FACULTY OF GRADUATE STUDIES THE FACULTY OF PHARMACEUTICAL SCIENCES Division of Pharmacology and Toxicology We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA April 1991 © Rajesh Mahey, 1991 ln presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. 1 further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Pharmacology. Faculty of Pharmaceutical Sciences The University of British Columbia Vancouver, Canada ' Date April 30, 1991 DE-6 (2/88) A B S T R A C T The aim of the present investigation was to determine whether a plasma membrane high affinity C a 2 + - A T P a s e plays an integral role i n the maintenance of cytoplasmic free C a 2 + in pancreatic acinar cells. To achieve this, the C a 2 + -transport and C a 2 + - A T P a s e activities were characterized and their properties compared. Plasma membranes from guinea-pig pancreatic acini were shown to contain a n ATP-dependent high affinity C a 2 + - p u m p and a high affinity C a 2 + -dependent ATPase activity. In addition, a low affinity ATPase activity was also observed. The high affinity C a 2 + - A T P a s e activity as well as the Ca 2 + - transport were found to be dependent on M g 2 + , whereas the low affinity ATPase activity appeared to be in…
has type: Thesis/Dissertation
date issued: 1991-05
is shown at: 10.14288/1.0100416
language: eng
degree discipline: Pharmaceutical Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/31044