Calcium and sodium transport processes in patients with cystic fibrosis part 2 magnesium ion dependent calcium ion atpase activity in fibroblast membrane preparations from cystic fibrosis patients and controls/
Research Communications in Chemical Pathology and Pharmacology 19(3): 491-504
ISSN/ISBN: 0034-5164 Accession: 004866730
Mg2+-dependent Ca2+-ATPase activity was determined in membrane preparations of fibroblasts grown from skin biopsies of cystic fibrosis patients and age-matched controls. This enzyme was stimulated by increasing free Ca2+ concentrations with an apparent Kd for Ca2+ of approximately 45 .mu.M. Although there was a great deal of variation in Ca2+-ATPase activity observed between individual strains, there was a significant decrease in the maximal activation of the Ca2+-ATPase in membrane preparations of fibroblasts obtained from cystic fibrosis patients compared to the controls (P < 0.05). This observation indicates that decreased Ca2+-ATPase activity is a generalized phenomenon in cystic fibrosis found in more than 1 cell-type. This decrease in Ca2+-ATPase activity may have a number of implications that may explain some of the manifestations of the disease.