Vitale L, Skrtić I, Abramić M
Department of Organic Chemistry and Biochemistry, Ruder Bosković Institute, Bijenicka c. 54, 10001 Zagreb, Croatia.
Arch Microbiol. 1996 Jun;165(6):409-14. doi: 10.1007/s002030050345.
An aminopeptidase from the mycelia of Streptomyces rimosus was isolated in an electrophoretically homogeneous form. It was shown to be a monomeric, acidic protein (pI = 4.4, mol. wt. approx. 83,000), with optimal activity at pH 7.1-7.8 and at 35-41 degrees C. The enzyme was fully inhibited by 0.1 mM EDTA or 1 mM o-phenanthroline; the activity was restored upon addition of 0.05 mM Co2+, Zn2+, or Ni2+. Amastatin, bestatin, and puromycin also inhibited the enzyme. The aminopeptidase hydrolyzed amino-acid-2-naphthylamides and various di- to heptapeptides. The highest catalytic coefficients (23 and 19 microM-1 s-1) were obtained with Arg- and Lys-2-naphthylamide, followed by Leu-, Phe- and Met-derivatives with one order of magnitude lower catalytic coefficients. Basic or bulky hydrophobic amino acids at the P1 and/or P1' position of peptide substrates were preferred. Acidic amino acids and proline were not accepted. The affinity of the enzyme increased with the length of peptide. According to these properties, S. rimosus intracellular aminopeptidase is distinct from the extracellular leucine aminopeptidase of the same organism and can be classified as an Arg(Lys)-preferring metalloaminopeptidase.
从龟裂链霉菌菌丝体中分离出一种电泳纯的氨肽酶。结果表明，它是一种单体酸性蛋白（pI = 4.4，分子量约83,000），在pH 7.1 - 7.8和35 - 41℃时具有最佳活性。该酶被0.1 mM EDTA或1 mM邻菲罗啉完全抑制；添加0.05 mM Co2 +、Zn2 +或Ni2 +后活性恢复。氨肽素、贝他汀和嘌呤霉素也抑制该酶。这种氨肽酶能水解氨基酸 - 2 - 萘酰胺和各种二肽至七肽。用精氨酸 - 和赖氨酸 - 2 - 萘酰胺获得最高催化系数（23和19 μM-1 s-1），其次是亮氨酸 -、苯丙氨酸 - 和甲硫氨酸 - 衍生物，其催化系数低一个数量级。肽底物P1和/或P1'位置的碱性或大体积疏水氨基酸是优选的。酸性氨基酸和脯氨酸不被接受。该酶的亲和力随肽长度增加而增加。根据这些特性，龟裂链霉菌细胞内氨肽酶不同于同一生物体的细胞外亮氨酸氨肽酶，可归类为偏好精氨酸（赖氨酸）的金属氨肽酶。
