Lysozymes: Model Enzymes in Biochemistry and Biology

More than seventy years after Fleming's discovery of lysozyme, this enzyme continues to play a crucial role as a model enzyme in protein chemistry, enzymology, crystallography, molecular biology and genetics, immunology and also in evolutionary biology. The classical representative of this widespread enzyme family is the hen egg-white lysozyme. Chicken (c)-type lysozymes have also been characterized in many other animals including mammals, reptiles and invertebrates. Besides this c-type lysozyme, other distinct types, differing on the basis of structural, catalytic and immunological critera, have been described as well, these in birds, phages, bacteria, fungi, invertebrates and plants. The specificity, however, of all these enzymes is the same: they cleave a ß-glycosidic bond between the C-1 of N-acetylmuramic acid and the C-4 of N-acetylglucosamine of the bacterial peptidoglycan. In this volume special emphasis is placed on results obtained during the last ten years. Lysozymes are by no means merely defence or, in certain cases, digestion enzymes. In fact, peptidoglycan fragments released by the lytic action of this enzyme family can trigger the synthesis of immunostimulating or antibacterial substances, and a host of other unexpected, biological reactions may be provoked by lysozymes as well. As Fleming has prophesized: ''We shall hear more about lysozyme''.