posted on 2022-02-01, 19:34authored byMathias Jaeser, Ulrike Moeckel, Kati Weigel, Thomas Henle
Using reversed phase
high-performance liquid chromatography with
ultraviolet (UV) detection and electrospray ionization (ESI)-quadrupole
time-of-flight mass spectrometry (RP-HPLC-UV-ESI-Q-TOF), the lysozyme
content in the milk of 10 volunteering mothers was quantified, ranging
from 29 to 96 μg/mL. Following ultracentifugation, it was found
that the lysozyme in human milk, unlike other whey proteins, is mainly
bound to casein micelles (ca. 75%). The enzymatic activity of human
lysozyme, measured as lytic activity against cell walls of Micrococcus lysodeikticus, was similar for the micelle-bound
and free protein, indicating that the micellar structure should not
affect the antibacterial activity of lysozyme. The results indicate
that lysozyme is an integral component of casein micelles in human
milk.