Clearing of Suspensions of Micrococcus lysodeikticus Catalysed by Lysozymes from Hen, Goose, and Turkey Egg Whites, Human Milk, and Phage T4. Assessment of Potential as Signal Generators for Homogeneous Enzyme Immunoassays for Urinary Steroids

Abstract

Lysozymes (3.2.1.17) from goose (Anser anser) egg white, turkey (Melagris gallopavo) egg white, phage T4 and human milk were compared with hen egg white lysozyme in their ability to clear a suspension of Micrococcus lysodeikticus. All of the lysozymes, except hen egg white lysozyme, catalysed the clearing of the Micrococcus lysodeikticus suspension in a biphasic fashion. Compared to hen egg white lysozyme, the total absorbance or transmission change over 5 and 20 minutes was less in all cases, except for human lysozyme. Human lysozyme was, therefore, a potential alternative, more rapid signal generator for the measurement of urinary estrone glucuronide excretion rates because of its structural similarity to hen egg white lysozyme. The apparent KM values for hen egg white lysozyme increased with the enzyme concentration.