Chatterjee R, Kalnitsky G
Biomed Biochim Acta. 1986;45(11-12):1447-55.
Ten peptides were tested as substrates for cathepsin I. The enzyme exerted both endopeptidase and aminopeptidase activities on 5 substrates, only aminopeptidase activity on 3 others, and only endopeptidase cleavage on one compound. One peptide was not significantly hydrolyzed. Aminopeptidase activity stopped one residue before a proline residue and endopeptidase cleavage took place one residue after a proline residue. With these substrates, this enzyme appears to have a broad specificity in its aminopeptidase action. However, cathepsin I appears to have a much narrower and more specific endopeptidase activity, hydrolyzing peptide bonds involving the nitrogen of branched chain or bulky or hydrophobic amino acids. Finally, some differences in the physical, chemical and biological properties of cathepsins H and I were discussed.
测试了十种肽作为组织蛋白酶I的底物。该酶对5种底物同时发挥内肽酶和氨肽酶活性，对另外3种底物仅发挥氨肽酶活性，对一种化合物仅进行内肽酶切割。有一种肽未被显著水解。氨肽酶活性在脯氨酸残基前一个残基处停止，内肽酶切割在脯氨酸残基后一个残基处发生。对于这些底物，该酶在其氨肽酶作用中似乎具有广泛的特异性。然而，组织蛋白酶I似乎具有更窄且更具特异性的内肽酶活性，水解涉及支链、大体积或疏水氨基酸氮的肽键。最后，讨论了组织蛋白酶H和I在物理、化学和生物学性质上的一些差异。
