DESCRIPTION

PDZ-binding kinase (PBK) is also named as spermatogenesis-related protein kinase (SPK), cancer/testis antigen 84 (CT84) and Nori-3. PBK is an enzyme that promotes the proliferation and spread of cancer cells. PBK is an oncogenic protein that plays vital roles in the proliferation, progression, and metastasis of many malignancies. PBK contributes to tumor cell development and doxorubicin resistance via physically interacting with p53 and downregulating its function. PBK, also known as T-lymphokineactivated killer-cell-originated protein kinase (TOPK), is a serine/threonine kinase that participates in cell cycle regulation and mitotic progression.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with HRP) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with HRP also binds to the analyte. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	8	16.06	0.52	3.25
2	8	3.71	0.26	6.90
3	8	1.99	0.07	3.51

Inter-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	16	15.14	1.24	8.21
2	16	3.54	0.29	8.10
3	16	1.85	0.16	8.74

RECOVERY

The recovery of human PBK spiked to three different levels throughout the range of the assay in cell lysate was evaluated.

Sample Type		Average% of Expected	Range (%)
Cell lysate	1:80	122	117-129

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The cell lysate was initially diluted 1:10.)

		Cell lysate
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	97
	Range (%)	96-98
1:8	Average% of Expected	93
	Range (%)	90-96
1:16	Average% of Expected	97
	Range (%)	96-98

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human PBK Sandwich ELISA Kit produced at Sunlong Medical™.