Conjugation of Estrone Glucuronide with Human Lysozyme

Abstract

Human milk lysozyme was conjugated with estrone glucuronide to give a monoacylated conjugate, two disubstituted isoforms, and one trisubstituted isoform in 99.4% yield. The conjugates were pure and highly inhibited (>98%) by the anti-estrone glucuronide antibody. The clearing curves were biphasic for all four conjugates but a 3 min initial rate assay was established and used to measure a normal menstrual cycle profile of estrone glucuronide excretion rates. The marked differences between the hen egg white and human milk lysozyme conjugates show that near identical tertiary structures do not necessarily imply similar physical, chemical, biochemical, and kinetic behavior.

Keywords:

• Human lysozyme
• conjugation
• estrone glucuronide

ACKNOWLEDGMENTS

A special thanks is due to Dr. Todd Kagawa for the generous donation of his time and skill with the lysozyme structural comparisons and to Dr. Simon Brown of the Deviot Institute (Tasmania) for his valuable assistance in preparation of this article.