Linked Life Data

1906783

Source:http://linkedlifedata.com/resource/pubmed/id/1906783

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1991-8-28
pubmed:abstractText
The accurate calibration of Fura-2 fluorescence in living cells is dependent upon the apparent dissociation constant (Kd) of Fura-2 for Ca2+. If Ca-EGTA calibration buffers are used to construct an in vitro calibration curve, then the calculated value of the apparent Ca-EGTA association constant (K'CaEGTA) will have an important influence on the Kd of Fura-2 and thus the calculated free [Ca2+] in cells. In order to simulate experimental conditions, the individual proton and Ca2+ association constants for EGTA in these experiments were adjusted for both ionic strength and temperature using a semi-empirical form of the Debye-Huckel limiting law and the Van't Hoff isochore, respectively, as described by Harrison and Bers. The modified individual binding constants were then employed in the calculation of K'CaEGTA using the SPECS computer program of Fabatio. At pH = 7.05, ionic strength = 0.15 M, temp = 20 degrees C, K'CaEGTA = 3.232 x 10(6) M-1; at pH = 6.84, temp = 36 degrees C, K'CaEGTA = 1.652 x 10(6) M-1. These values differed substantially from those obtained with unadjusted individual association constants. Calibration buffers of varying [Ca2+] were prepared using the corrected values of K'CaEGTA, and Fura-2 fluorescence ratios were measured during superfusion of these buffers in the experimental chamber at both 20 degrees C and 37 degrees C. The Kd of Fura-2 for Ca2+ was determined to be 236 nM at 20 degrees C and 285 nM at 37 degrees C, utilizing the value of K'CaEGTA adjusted by the method of Harrison and Bers.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0143-4160
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
279-87
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Determination of Fura-2 dissociation constants following adjustment of the apparent Ca-EGTA association constant for temperature and ionic strength.
pubmed:affiliation
Department of Cardiology, Marshfield Clinic & Research Foundation, Wisconsin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't