HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pepper, L. Articles by Thompson, M. P. Search for Related Content PubMed Articles by Pepper, L. Articles by Thompson, M. P.

Dephosphorylation of _S- and -Caseins and Its Effect on Micelle Stability in the -_S-Casein System

Eastern Regional Research Laboratory,¹ Philadelphia, Pennsylvania

ABSTRACT

_S- and -Caseins, obtained from commercial pooled milk, were dephosphorylated with a phosphoprotein phosphatase prepared from beef spleen. Ultracentrifuge studies at pH 7.0 on 1:4 (:_S) weight ratios of the dephosphorylated proteins gave patterns consisting of a major peak, S₂₀ = 7.5, and a barely discernible minor peak, S₂₀ = 4.4. For a similar mixture that had been maintained at pH 12.0 for 10 min before ultracentrifugation at pH 7.0 a single peak, S₂₀ = 7.5, was obtained. The native - and _S-caseins in 1:4 (:_S) weight ratios gave only a single peak, S₂₀ = 7.5, under both of the above conditions.

Micelle stability of mixtures of the dephosphorylated proteins with the native - and _S-caseins were compared. The stabilizing power of -casein was not changed significantly by dephosphorylation, but the dephosphorylation of _S-casein impaired drastically its ability to be stabilized by -casein in the presence of 0.02 M CaCl₂ at pH 7.0.

¹ Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.