溶菌酶（lysozyme）又稱胞壁質酶（muramidase）或N-乙酰胞壁質聚糖水解酶（N-acetylmuramide glycanohydrlase），是一種能水解致病菌中黏多糖的酶。在自然界中，溶菌酶普遍存在于鳥類、家禽的蛋清和哺乳動物的眼淚、唾液、血液、鼻涕、尿液、乳汁和組織細胞中(如肝、腎、淋巴組織、腸道等) ，從植物中也能分離出溶菌酶（如木瓜、蕪青、大麥、無花果和卷心菜、蘿卜等）。

Lysozyme, also known as muramicase or N-acetylmuramicide glycolase, is an enzyme that can hydrolyze mucopolysaccharides in pathogenic bacteria. In nature, lysozyme is commonly found in the egg whites of birds and poultry, as well as in the tears, saliva, blood, nasal mucus, urine, milk, and tissue cells of mammals (such as liver, kidney, lymphoid tissue, intestine, etc.). Lysozymes can also be isolated from plants (such as papaya, turnip, barley, figs, cabbage, radish, etc.).