A REEXAMINATION OF SOME PROPERTIES OF FATTY ACYL-COA MICELLES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 256  (24) , 2740-2747
Abstract
Three separate techniques were employed to estimate the critical micelle concentration: spin labeling using 6-doxylstearoyl-CoA, gel permeation chromatography, and analytical ultracentrifugation. The 1st method is a labeling technique. The latter 2 methods utilize no potentially interfering probe and provide a value for the aggregation number for palmitoyl-CoA. All 3 methods provide a critical micelle concentration for palmitoyl-CoA no lower than 30-60 .mu.M. The latter methods provide an aggregation number near 40 and certainly no larger than 200. These values are inconsistent with the values suggested earlier. The spin-labeled analogs, 6- and 16-doxylstearoyl-CoA, were shown not to micellize, yet these analogs were good inhibitors for citrate synthase. These observations will require the re-examination of a large body of literature in which inhibition of enzymes by fatty acyl-CoA at concentrations below 30 .mu.M was simply ascribed to the formation of micelles.