ISSN:
0730-2312
Keywords:
erythrocytes
;
magnesium
;
echinocyte
;
calcium
;
plasma membrane
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Intact human erythrocytes, initially depleted of Mg2+ by EDTA incubation in the presence of A23187, exhibit Mg2+-dependent phosphate production of around 1.5 mmol per liter cells · h, half-maximally activated at around 0.4 mM added free Mg2+. This appears to correspond to Mg2+-stimulated adenosine triphosphatase (Mg2+-ATPase) activity found in isolated membranes, which is known to have a similar activity and affinity for Mg2+. Vanadate (up to 100 μM) inhibited Mg2+-dependent phosphate production and ATP breakdown in intact cells. Over a similar concentration range vanadate (3-100 μM) transformed intact cells from normal discocytes to echinocytes within 4-8 h at 37°C, and more rapidly in Mg2+-depleted cells. The rate of Ca2+-induced echinocytosis was also enhanced in Mg2+-depleted cells. These results support previous studies in erythrocyte ghosts suggesting that vanadate-induced shape change is associated with inhibition of Mg2+-ATPase activity localized in the plasma membrane of the red blood cell.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240460403
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