Treatment of Casein Micelles with Soluble and Immobilized Neuraminidase: Implications in Structure of the Micelle

Abstract
Bovine casein micelles were isolated from raw, uncooled skim milk by ultracentrifugation, washing and resuspending in simulated milk ultrafiltrate. They were reacted with soluble and immobilized neuraminidase in studies on the kinetics of release of sialic acid. Almost all of the sialic acid was released with soluble neuraminidase; only 88% was released with immobolized neuraminidase. After casein solublization is accounted for, it appears that at least 75% of the glyco-.kappa.-casein is on the micelle surface.