Georgieva D N, Stoeva S, Ivanova V, Gusterova A, Voelter W
Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia.
Curr Microbiol. 2000 Jul;41(1):70-2. doi: 10.1007/s002840010094.
The proteolytic specificity of the neutral Zn-dependent proteinase from Thermoactinomyces sacchari was determined by analysis of the peptides obtained after incubation with the oxidized insulin B chain as a substrate. The enzyme is an endopeptidase with broad specificity. In total, 12 peptide bonds in the B chain of insulin were hydrolyzed. The major requirement is that a hydrophobic residue such as Leu, Val, or Phe should participate with the alpha-amino group in the bond to be cleaved. However, hydrolysis of bonds at the N-terminal side of His, Thr, and Gly was also observed. The peptide bond Leu 15-Tyr 16 in the oxidized insulin B chain, which is the major cleavage site for the alkaline microbial proteinases, is resistant to the attacks of the enzyme from Thermoactinomyces sacchari and other neutral proteinases. The proteolytic activity of the Zn-dependent proteinase from T sacchari is different from those of other metalloendopeptidases from microorganisms.
通过分析以氧化胰岛素B链为底物孵育后获得的肽段，确定了嗜热放线菌中性锌依赖性蛋白酶的蛋白水解特异性。该酶是一种具有广泛特异性的内肽酶。胰岛素B链中共有12个肽键被水解。主要要求是疏水性残基（如亮氨酸、缬氨酸或苯丙氨酸）应与α-氨基一起参与被切割的键。然而，也观察到组氨酸、苏氨酸和甘氨酸N端侧的键发生水解。氧化胰岛素B链中的Leu 15-Tyr 16肽键是碱性微生物蛋白酶的主要切割位点，对嗜热放线菌的酶和其他中性蛋白酶的攻击具有抗性。嗜热放线菌锌依赖性蛋白酶的蛋白水解活性与其他微生物金属内肽酶的活性不同。
