Suc-AAPF-pNA (Suc-Ala-Ala-Pro-Phe-pNA) is a colorimetrically specific substrate for elastase[1]. Under the action of enzymes, Suc-AAPF-pNA is hydrolyzed, releasing yellow p-nitroaniline (pNA), and the change in absorbance at 400-410 nm is measured to reflect enzyme activity through colorimetry[2]. Suc-AAPF-pNA also serves as a substrate for cathepsin G, bacillus protease, chymotrypsin, chymotrypsin, cyclophilin, and peptidyl-prolyl isomerase[3] .
The structure and group characteristics of Suc-AAPF-pNA are as follows:
(1)Succinyl group (Suc): Increases the water solubility and stability of the substrate.
(2)Amino acid sequence (Ala-Ala-Pro-Phe): This specific sequence mimics certain natural substrates and helps study the specificity of proteases towards different substrates.
(3)p-Nitroaniline (pNA): A common chromophoric group that releases a yellow product with absorbance characteristics upon hydrolysis, facilitating the monitoring of enzyme reactions through spectrometry.
References:
[1] Vinci V A. Biochemical and genetic analysis of serine proteases of Streptomyces spp[M]. The Ohio State University, 1988.
[2] Chaves-Pozo E, Valero Y, Lozano M T, et al. Fish granzyme A shows a greater role than granzyme B in fish innate cell-mediated cytotoxicity, Front. Immunol. 10 (2019) 2579[J]. 2019.
[3] Attucci S, Korkmaz B, Juliano L, et al. Measurement of free and membrane-bound cathepsin G in human neutrophils using new sensitive fluorogenic substrates[J]. Biochemical Journal, 2002, 366(3): 965-970.
Suc-AAPF-pNA（Suc-Ala-Ala-Pro-Phe-pNA）是弹性蛋白酶的比色特异性底物[1]。Suc-AAPF-pNA在酶的作用下水解，释放出黄色的对硝基苯胺（pNA），通过比色法测定400-410nm处吸光度的变化来反映酶活性[2]。Suc-AAPF-pNA还充当组织蛋白酶 G、枯草杆菌蛋白酶、糜蛋白酶、糜蛋白酶、亲环蛋白和肽基脯氨酰异构酶的底物[3]。
Suc-AAPF-pNA的结构和基团特点如下：
（1）琥珀酰基团（Suc）：增加底物的水溶性和稳定性。
（2）氨基酸序列（Ala-Ala-Pro-Phe）：这一特定序列模仿了某些天然底物，有助于研究蛋白酶对不同底物的特异性。
（3）对硝基苯胺（pNA）：是一个常见的色原基团，水解后释放出具有吸光特性的黄色产物，方便通过光谱测定监测酶反应。