KLK5 protein (kallikrein-related peptidase 5) is a secreted serine protease encoded by the KLK5 gene, featuring a signal peptide and a catalytically active trypsin-like domain in its structure, with predominant expression in epithelial tissues such as skin and salivary glands. Physiologically, KLK5 participates in epidermal desquamation by cleaving cell adhesion molecules and activates antimicrobial peptide precursors to maintain skin barrier homeostasis, while also serving as a key host protease that cleaves coronavirus spike proteins to facilitate viral entry. Clinically, aberrant expression of KLK5 is closely associated with multiple diseases: its dysregulated activity can lead to inflammatory skin disorders including Netherton syndrome, atopic dermatitis, and rosacea; in oncology, it exhibits a complex dual role—with high expression in ovarian cancer indicating poor prognosis, whereas low expression in testicular cancer correlates with advanced disease progression. In recent years, it has also been linked to low type 2 inflammation-associated asthma, establishing KLK5 as an important therapeutic target for the development of anti-coronavirus and anti-inflammatory skin disease drugs.

高纯度、高活性、低内毒素、高批间一致性

实验方法

实验原理：检测KLK5切割荧光肽底物Boc-VPR-AMC的能力。

实验材料

1. 检测缓冲液：0.1 M NaH2PO4, pH 8.0

2. KLK5/Kallikrein 5 His Tag Protein, Human

3. 底物：BOC-Val-Pro-Arg-AMC (R&D systems, Catalog # ES011)

4. 96 ELISA Removable Plate, Black, High binding (GENEVER, Catalog # GMO2-96H)

5. 读板器（PerkinElmer，激发波长380 nm，发射波长460 nm）

实验步骤

1. 用检测缓冲液将KLK5蛋白稀释至8 μg/mL、4 μg/mL、2 μg/mL三个浓度。

2. 用检测缓冲液将底物稀释至200 μM。

3. 每孔加入50 μL稀释后的KLK 5蛋白，再加入50 μL浓度200 μM的底物启动酶促反应；同时设置底物空白对照组：每孔加入50 μL检测缓冲液+ 50 μL 200 μM底物。

4. 在激发波长380 nm，发射波长460 nm条件下，以动力学模式读数10分钟。

标准曲线制作步骤

1. 用检测缓冲液将校准标准品稀释至10 μM，并进行梯度倍比稀释。

2. 96孔板对应孔中分别加入100 μL各梯度稀释标准品，以及100 μL检测缓冲液作为空白对照；标准曲线每孔终含量梯度为：1000, 500, 250, 125, 62.5, 31.3, 15.6, 7.8 pmol。

3. 终点法读取荧光信号，激发波长380 nm，发射波长460 nm。

4. 以7-氨基- 4 - 甲基香豆素含量（pmol，y轴）对扣除空白后的相对荧光单位（RFU-Blank，x轴）做线性回归拟合：

-25 ~ -15℃保存，收到货之后有效期1年。
复溶后， 无菌条件下，-85 ~ -65℃保存，3个月有效期。复溶后， 无菌条件下，2 ~ 8℃保存，1周有效期。