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Stability characteristics of deuterated myoglobin

Stability characteristics of deuterated myoglobin Purified sperm whale myoglobin was deuterated by being exposed to pD 3.5 in D2O buffer for 1 hr, then raised to pD 10.6 for an additional hour, and finally brought to neutrality in a D2O environment. Control myoglobin was similarly treated in H2O. The specific rotation at 233 mμ and/or the absorbance in the Soret region were used to follow the helix‐coil transition of myoglobin subjected to denaturation by acid, alkali, urea and guanidine. Deuterated and control myoglobin had similar 50% transition points in the four denaturing media studied (acid: pH 4.4, pD 4.9; alkali: pH 9.4, pD 10.0; urea, 7.2M; guanidine, 2.5M). The shift toward the alkaline side of 0.5 or 0.6 units of the transition induced by either acid or alkaline denaturation reflects only the weakened acidity of ionizable groups in deuterium systems. Deuterated myoglobin in 3.25M guanidine had a 20% faster denaturation rate than that of control. Acid, urea, and guanidine denaturation curves showed fairly steep transitions, taken as indicative of a one‐step process involving only two states (native and denatured molecules). Supporting this conclusion was the fact that plots of absorption and polarimetry measurements of the helix‐coil transition induced by either acid or guanidine could be superimposed. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Biopolymers Wiley

Stability characteristics of deuterated myoglobin

Biopolymers , Volume 10 (11) – Nov 1, 1971

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References (21)

Publisher
Wiley
Copyright
Copyright © 1971 John Wiley & Sons, Inc.
ISSN
0006-3525
eISSN
1097-0282
DOI
10.1002/bip.360101122
pmid
5165788
Publisher site
See Article on Publisher Site

Abstract

Purified sperm whale myoglobin was deuterated by being exposed to pD 3.5 in D2O buffer for 1 hr, then raised to pD 10.6 for an additional hour, and finally brought to neutrality in a D2O environment. Control myoglobin was similarly treated in H2O. The specific rotation at 233 mμ and/or the absorbance in the Soret region were used to follow the helix‐coil transition of myoglobin subjected to denaturation by acid, alkali, urea and guanidine. Deuterated and control myoglobin had similar 50% transition points in the four denaturing media studied (acid: pH 4.4, pD 4.9; alkali: pH 9.4, pD 10.0; urea, 7.2M; guanidine, 2.5M). The shift toward the alkaline side of 0.5 or 0.6 units of the transition induced by either acid or alkaline denaturation reflects only the weakened acidity of ionizable groups in deuterium systems. Deuterated myoglobin in 3.25M guanidine had a 20% faster denaturation rate than that of control. Acid, urea, and guanidine denaturation curves showed fairly steep transitions, taken as indicative of a one‐step process involving only two states (native and denatured molecules). Supporting this conclusion was the fact that plots of absorption and polarimetry measurements of the helix‐coil transition induced by either acid or guanidine could be superimposed.

Journal

BiopolymersWiley

Published: Nov 1, 1971

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