Clinical Chemistry
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 20: 794-801, 1974;
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Burke, R. W.
Right arrow Articles by Menis, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Burke, R. W.
Right arrow Articles by Menis, O.

Clinical Chemistry, Vol 20, 794-801, Copyright © 1974 by the American Association for Clinical Chemistry

Mechanisms of the Liebermann-Burchard and Zak Color Reactions for Cholesterol

R. W. Burke 1, B. I. Diamondstone 1, R. A. Velapoldi 1, and O. Menis 1

1 Analytical Chemistry Division, Institute for Materials Research, National Bureau of Standards, Washington, D. C. 20234.

Correlation of SO2 and Fe2+ measurements with new spectral data indicates that the Liebermann-Burchard (L-B) and Zak color reactions for cholesterol have similar oxidative mechanisms, each yielding, as oxidation products, a homologous series of conjugated cholestapolyenes. These studies further suggest that the colored species observed in these two systems are enylic carbonium ions formed by protonation of the parent polyenes. Thus, the red (lgrmax, 563 nm) product typically measured in the Zak reaction is evidently a cholestatetraenylic cation, and the blue-green product in the L-B reaction (lgrmax, near 620 nm) is evidently the pentaenylic cation. The effects of rate of carbonium ion formation and sulfuric acid concentration on sensitivity and color stability are discussed. A solvent extraction procedure is described for specifically converting cholesterol to 3,5-cholestadiene. Incorporating this step into the typical L-B method can increase the L-B sensitivity for cholesterol by several fold.


Key Words: cholestapolyenes • conjugated double bonds • carbonium ions from polyenes • factors affecting color • SO2 and Fe2+ measurement • equivalent ratios

Submitted on January 4, 1974
Accepted on May 7, 1974




The following articles in journals at HighWire Press have cited this article:


Home page
 Biol. Reprod.Home page
J. Girouard, G. Frenette, and R. Sullivan
Compartmentalization of Proteins in Epididymosomes Coordinates the Association of Epididymal Proteins with the Different Functional Structures of Bovine Spermatozoa
Biol Reprod, May 1, 2009; 80(5): 965 - 972.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Reprod.Home page
J. Girouard, G. Frenette, and R. Sullivan
Seminal Plasma Proteins Regulate the Association of Lipids and Proteins Within Detergent-Resistant Membrane Domains of Bovine Spermatozoa
Biol Reprod, May 1, 2008; 78(5): 921 - 931.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Reprod.Home page
H. Rejraji, B. Sion, G. Prensier, M. Carreras, C. Motta, J.-M. Frenoux, E. Vericel, G. Grizard, P. Vernet, and J. R. Drevet
Lipid Remodeling of Murine Epididymosomes and Spermatozoa During Epididymal Maturation
Biol Reprod, June 1, 2006; 74(6): 1104 - 1113.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1974 by the American Association for Clinical Chemistry.