DESCRIPTION

Survival Motor Neuron (SMN) protein required for efficient assembly of small nuclear ribonucleoprotein (snRNP) complexes is encoded by nearly identical telomeric and centromeric forms of SMN gene respectively. Both the SMN1 and SMN2 genes express SMN protein, however, the amount of functional full-length protein produced by SMN2 is much less than that produced by SMN1 due to the alternative splicing. The SMN gene is constitutively expressed in wide variety of tissues including brain, kidney, liver and spinal cord, while motor neurons are particularly vulnerable to reduced SMN protein levels. Deletion or mutational inactivation of the SMN1 gene causes spinal muscular atrophy (SMA), a lethal genetic disease characterized by loss of motor neurons in the spinal cord. The absence of SMN1 can be partially compensated for by SMN2 and the SMN2 expression level is associated with SMA severity. This kit is for the quantitative determination of SMN protein level in vivo.

PRINCIPLE OF THE ASSAY

A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody also binds to the analyte. Horseradish peroxidase (HRP)-conjugated secondary antibody binds to the detection antibody. 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	1,037.6	63.2	6.1
2	20	1,678.6	71.1	4.2
3	20	2,465.5	98.0	4.0

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	1,219.4	93.9	7.7
2	24	2,594.4	152.6	5.9
3	24	4,296	252.7	5.9

RECOVERY

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

Sample Matrix(# of samples)	Required Dilution	SpikeConcentration (pg/mL)	Average% of Expected /Range (%)
Human cell lysate（n=4）	1:2	2,500	107（106-108）
		1,250	92（90-93）
		125	82（71-94）
	1:4	2,500	89（88-91）
		1,250	89（83-90）
		125	98（88-108）
Mouse skeletal muscle extract（n=4）	1:8	2,500	90（90-91）
		1,250	88（83-93）
		125	107 (93-121）
	1:16	2,500	107 (105-110)
		1,250	104 (95-112)
		125	112 (97-127)

LINEARITY

To assess the linearity of the assay, three samples were spiked with high concentrations of human/mouse SMN in various matrices and diluted with the appropriate Sample Diluent PT 3-af to produce samples with values within the dynamic range of the assay.

		Mouse muscle tissue	Human cell lysate
1:2	Average% of Expected	66	113
	Range (%)	62-71	101-124
1:4	Average% of Expected	79	111
	Range (%)	73-85	98-122
1:8	Average% of Expected	100	108
	Range (%)	100	100-116
1:16	Average% of Expected	114	98
	Range (%)	110-119	98-112

CALIBRATION

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

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
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• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)