Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/8347
Title: Binding and Release of Cations by Sarcoplasmic Reticulum before and after Removal of Lipid
Authors: Carvalho, Arsélio P. 
Issue Date: 1972
Citation: European Journal of Biochemistry. 27:3 (1972) 491-502
Abstract: The Ca2+ bound actively in the presence of ATP by sarcoplasmic reticulum isolated from rabbit skeletal muscle is released by Zn2+ (or Cd2+) as well as by phospholipases A or C and by trypsin. Zinc ions also release Mg2+ and are taken up passively by the reticulum membranes, whereas phospholipases A and C and trypsin release only the actively bound Ca2+. Phospholipase A, and to a smaller extent phospholipase C and trypsin, increase the passive cation-binding capacity of reticulum. Thus, concurrently with the loss of selectively bound Ca2+ caused by these agents, there is an increase in the passively bound Mg2+. The increase in the passive cation-binding capacity of reticulum induced by phospholipase depends on the presence of the splitting products of phospholipids, since their removal when digested reticulum is washed with a 2.5% albumin solution decreases the binding capacity to about 50% of the original value. When Ca2+, Mg2+ or Sr2+ is bound passively by reticulum, the ratio of H+ released to either of these divalent cations bound, expressed in terms of nequiv H+ released per nequiv divalent cation bound is about 1.0, but when Zn2+ is taken up, the ratio H+/Zn2+ is only about 0.5, which suggests that some of the Zn2+ is bound at sites that do not release H+ or bind Ca2+. After lipid extraction with 90% acetone, the cation-binding capacity and H+ release are decreased to about 40% of the original values. This effect is particularly evident between pH values of about 6.0 and 8.0. The apparent passive Ca2+-binding affinity is not affected by the lipid removal.
URI: http://hdl.handle.net/10316/8347
DOI: 10.1111/j.1432-1033.1972.tb01865.x
Rights: openAccess
Appears in Collections:FCTUC Ciências da Vida - Artigos em Revistas Internacionais

Files in This Item:
File Description SizeFormat
obra.pdf1.12 MBAdobe PDFView/Open
Show full item record

SCOPUSTM   
Citations

20
checked on Feb 18, 2020

WEB OF SCIENCETM
Citations

31
checked on May 29, 2020

Page view(s) 50

457
checked on Jul 30, 2020

Download(s) 20

1,076
checked on Jul 30, 2020

Google ScholarTM

Check

Altmetric

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.