S-adenosyl methionine (SAM) ELISA Kit

This assay employs a two-site sandwich ELISA to quantitate SAM in samples. An antibody specific for SAM has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any SAM present is bound by the immobilized antibody. After removing any unbound substances, a biotin-conjugated antibody specific for SAM is added to the wells. After washing, Streptavidin conjugated Horseradish Peroxidase (HRP) is added to the wells. Following a wash to remove any unbound avidin-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of SAM bound in the initial step. The color development is stopped and the intensity of the color is measured.
 

The deduced 361-amino acid protein has a calculated molecular mass of 42.1 kD. Viperin contains an N-terminal leucine zipper motif and a domain associated with iron-sulfur cluster coordination. Viperin shares significant homology with Best5, which is expressed during rat osteoblast differentiation, and Vig1, which is induced in rainbow trout infected with a fish rhabdovirus. The N-terminal leucine zipper motifs display the least homology. Western blot analysis of IFNG-treated macrophages and transfected HeLa cells revealed a major band of 43 kD and a minor band of 35 kD.HCMV infection caused redistribution of the induced viperin from its normal endoplasmic reticulum association, first to the Golgi apparatus and then to cytoplasmic vacuoles containing gB and the HCMV structural protein pp28.
 

Reagents	Quantity	Reagents	Quantity
Assay plate (96 Wells)	1	Instruction manual	1
Standard (lyophilized)	2	Sample Diluent	1 x 20 mL
Biotin-Conjugate (concentrate 100 x)	1 x 120 μL	Biotin-Conjugate Diluent	1 x 12 mL
Streptavidin-HRP  (concentrate 100 x)	1 x 120 μL	Streptavidin-HRP Diluent	1 x 12 mL
Wash Buffer (concentrate 25 x)	1 x 20 mL	Substrate Solution	1 x 10 mL
Stop Solution	1 x 6 mL	Adhesive Films	4

 

This assay has high sensitivity and excellent specificity for detection of General SAM. No significant cross-reactivity or interference between General SAM and analogues was observed.
 

Matrices listed below were spiked with certain level of recombinant General SAM and the recovery rates were calculated by comparing the measured value to the expected amount of General SAM in samples.
 

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in forty separate assays to assess inter-assay precision. CV (%) = SD/meanX100 Intra-Assay: CV<8% Inter-Assay: CV<12%
 

The linearity of the kit was assayed by testing samples spiked with appropriate concentration of General SAM and their serial dilutions. The results were demonstrated by the percentage of calculated concentration to the expected.
 

The stability of ELISA kit is determined by the loss rate of activity. The loss rate of this kit is less than 5% within the expiration date under appropriate storage condition. The loss rate was determined by accelerated thermal degradation test. Keep the kit at 37°C for 4 and 7 days, and compare O.D.values of the kit kept at 37°C with that of at recommended temperature. (referring from China Biological Products Standard, which was calculated by the Arrhenius equation. For ELISA kit, 4 days storage at 37°C can be considered as 6 months at 2 - 8°C, which means 7 days at 37°C equaling 12 months at 2 - 8°C).
 

Serum: Use a serum separator tube (SST) and allow samples to clot for two hours at room temperature or overnight at 2 - 8°C before centrifugation for 15 minutes at 1000 × g. Remove serum and assay immediately or aliquot and store samples at ≤ -20°C. Avoid repeated freeze-thaw cycles. Plasma: Collect plasma using EDTA, or heparin as an anticoagulant. Centrifuge for 15 minutes at 1000 × g at 2 - 8°C within 30 minutes of collection. Assay immediately or aliquot and store samples at ≤ -20°C. Avoid repeated freeze-thaw cycles. Other biological fluids: Centrifuge samples for 20 minutes at 1000 × g. Remove particulates and assay immediately or store samples in aliquot at -20°C or -80°C. Avoid repeated freeze/thaw cycles.
 

Store at 2-8°C. Please refer to Instruction Manual.