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终浓度为５ｍｍｏｌ／Ｌ的ＥＤＴＡ可彻底抑制粘质赛氏菌４１００３（２）胞外蛋白酶活力，而Ｃａ２＋可以回复部分酶活力，表明Ｃａ２＋为酶活力所必需；Ｚｎ２＋、Ｍｎ２＋、Ｆｅ２＋等金属离子对酶具有不同程度的抑制作用；５－磷酸吡哆醛及对甲氧基苯甲醛对酶具有明显的激活作用；以酪蛋白为底物，采用双倒数法求得酶的Ｋｍ值为６．６７ｍｇｍｌ－１；Ｎ，Ｎ－二甲基酪蛋白也是酶的理想底物；经酸水解，测定出酶的氨基酸组成；利用蛋白质自动分析仪测定了酶的Ｎ端９个氨基酸序列．比较来源不同的粘质赛氏菌胞外蛋白酶的Ｎ端序列，发现它们之间存在一定程度的同源性，并且存在特定的通读结构Ａｌａ…Ａｓｐ…Ｇｌｙ．
5 mmol / L EDTA could completely inhibit the extracellular protease activity of Listeria monocytogenes 41003 (2), while Ca2 + could recover part of the enzyme activity, indicating that Ca2 + is necessary for enzyme activity; metal ions such as Zn2 +, Mn2 + and Fe2 + Enzyme has different degree of inhibition; pyridoxal 5-phosphate and p-methoxybenzaldehyde have obvious activation of the enzyme; casein as a substrate, using the double countdown method to obtain the enzyme Km value of 6.67mgml -1; N, N-dimethyl casein is also an ideal substrate for the enzyme; by acid hydrolysis, the amino acid composition of the enzyme was determined; and the N-terminal 9 amino acid sequence of the enzyme was determined by a protein automated analyzer. Comparing the N-terminal sequence of X. marcescens extracellular protease with different origins, we found a certain degree of homology between them, and there is a specific universal structure Ala ... Asp ... Gly.