DESCRIPTION

SOD1 (Cu/Zn Superoxide Dismutase), also known as hemocuprein and IPOA (PMID: 5389100). SOD1 plays a role in cellular defense against oxidative stress. It neutralizes superoxide radicals, a type of reactive oxygen species (ROS) generated during normal cellular processes. By eliminating superoxide radicals, SOD1 protects cells from oxidative damage and maintains cellular health (PMID: 24140062). Mutations in SOD1 is linked to familial amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease affecting nerve cells in the brain and spinal cord (PMID: 20644736).

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with biotin) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with biotin also binds to the analyte. Streptavidin-HRP binds to the biotin. 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 20 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 24 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	20	2,447.4	146.0	6.0
2	20	615.5	26.0	4.2
3	20	140.1	12.5	8.9

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	2,341.0	131.3	5.6
2	24	603.7	36.2	6.0
3	24	164.5	14.8	9.0

RECOVERY

The recovery of human SOD1 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:40	101	87-119
	1:80	99	88-112

LINEARITY

To assess the linearity of the assay, human plasma samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The human plasma samples were initially diluted 1:5. )

		human plasma
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	97
	Range (%)	84-105
1:8	Average% of Expected	96
	Range (%)	80-111
1:16	Average% of Expected	99
	Range (%)	83-121

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human SOD1 produced at Sunlong Medical™.