ELISA Research FAQs

This indicator measures all subtypes of IFNα, that is, total IFNα. The standard is not a mixture of all subtypes, but human IFN-alpha 2a (recombinant protein, expression system: HEK293 cells). However, since the homology of the 15 IFN-α subtypes in humans is as high as 80%, the antibodies used in our kit can recognize all subtypes, and this kit has been verified for different subtypes of IFN-α, which can be detected.

Since the antibodies in the kit recognize activated TGF-β, and TGF-β is a disulfide bond linked by two identical or similar 12.5kDa subunits of molecular weight. The study of human TGF-β cDNA sequence showed that the 112 amino acid residues of the monomer TGF-β were cleaved from the carboxyl terminal by a precursor molecule (per-pro-TGF-β) containing 400 amino acid residues. The N-terminal of per-pro-TGF-β contains a signal peptide, which is cleaved before secretion to become an inactive polypeptide chain precursor (pro-TGF-β). The n-terminal part of the amino acid residue is removed by changing the ionic strength, acidification or protease hydrolysis, and the remaining carboxyl terminal part forms an active TGF-β. A variety of cells in the body can secrete TGF-β in an inactive state. In vitro, the inactive TGF-β, also known as latency associated peptide (LAP), can be activated by acidification. In vivo, the acidic environment can be present near fractures and healing wounds, and the cleavage of the protein itself can cause the TGF-β complex to become activated TGF-β. In general, tissues with active cell differentiation often contain high levels of TGF-β, such as osteoblasts, kidney, bone marrow, and fetal liver hematopoietic cells. Therefore, no additional activation processing is required for tissue sample testing.

These two kits can be used for the detection of your cell supernatant. However, ELISA detection of cell supernatants is affected by factors such as media components, cell growth, and external drug stimulation conditions, and it is recommended that you conduct a preliminary experiment before the formal experiment. Gelatin enzyme spectrometry uses the reversible combination of SDS and MMPs in the sample to separate MMP-2 and MMP-9 in the sample, and then restores the activity of both through the bivalent metal ion buffer system. This test method is specifically aimed at the activity detection of MMP-2 and MMP-9. ELISA detects the content (that is, concentration) of the tested substance through the binding reaction of antigen and antibody, that is, captures the MMP-2 and MMP-9 of the sample through the specific antibodies of MMP-2 and MMP-9. The experimental principles of the two are different, and the activity of MMP-2 and MMP-9 cannot be detected by ELISA.

VEGFA (VEGF) has a variety of subtypes (shear isomers), of which VEGF165 is the most abundant and effective VEGFA subtype (P15692-4), VEGF165 kit detection is the VEGF165A you mentioned, and VEGF165B is another shear body (P15692-8).

Collagen (COL1) consists of three peptide chains, two of which are α(Ⅰ) chain, COL1α1, and one α(Ⅱ) chain, col1α2. The homology between the two was 60.396%, and there was no obvious cross-reaction.

uPAR is a membrane binding receptor for uPA, also known as urokinase and hyaline. suPAR is caused by the splitting and release of membrane-bound uPAR and is the soluble form of uPAR. The kit measures total uPAR, both in membrane form and in soluble form.

In mammals, the APP gene is located on chromosome 21 and has a total of 8 subtypes, whose subtypes generally contain 365~770 amino acid residues. The most common are APP695, APP751, and APP770, of which APP695 is highly expressed in the central nervous system. APP is a type I transmembrane glycoprotein with a molecular weight of about 110~130 kDa, with a large extracellular (amino terminal) domain and a small cytoplasmic tail region (intracellular carboxyl terminal). APP is metabolized mainly through two pathways: amyloid (β) pathway and non-amyloid (α) pathway. The amyloid pathway is that APP is cleaved by β-secretase into sAPPβ and a C-terminal fragment containing 99 amino acids. The latter is further cleaved by γ-secreting enzymes into Aβ and ACID, and the Aβ generated by this pathway accounts for 90% to 95% of the total Aβ, including two types of Aβ1-40 and Aβ1-42, of which the content of Aβ1-40 is higher, but Aβ1-42 has A strong hydrophobic effect, its toxicity is greater, and it is easy to polymerization. These Aβ fragments accumulate in mitochondria, lysosomes, and the endoplasmic reticulum, causing these suborganelles to malfunction. In the non-starchy source pathway based on alpha secretase, the alpha secretase cuts APP into sAPP and a C-terminal fragment containing 83 amino acids, which is then cut by gamma secretase to produce P3 and ACID, but these small fragments are cleared by neurons. The mutation of APP gene can cause abnormal protein expression or hydrolysis change, thus affecting the content and composition of Aβ in cells. Aβ mainly exists in the brain in the form of Aβ40 and Aβ42, and the content of Aβ42 is low (< 10%), but easy to aggregate, and then fibrosis and deposition, thus forming a diffuse senile plaque, which is also one of the main pathological characteristics of AD. Moreover, Aβ produced by APP after cleavage by β- and γ-secretory enzymes on the cell membrane can cause oxidative stress, calcium ion inflow, and then damage mitochondria, leading to nerve cell disorders, activation of apoptosis-related proteins and factors, and finally start the apoptosis process of cells. In addition, Aβ can also indirectly cause neuronal apoptosis by causing inflammation in the brain and neurofibrillary tangles, which is an important reason for the formation and development of AD.

Most substances can be relatively stable under freezing conditions, but it is recommended to use newly collected samples for testing to obtain more accurate results. There are three kinds of methods for PAF detection: ① biological detection method; ② Physicochemical method; ③ Immunological methods. ELISA assay recommends adding 1mM TPCK or TLCK to the plasma sample to inhibit the activity of PAF-AH.

These two belong to different types of prostaglandins. Prostaglandin E2 (PGE2) is the most abundant prostaglandin and is produced by the action of prostaglandin E synthetase on prostaglandin H2(PGH2). Prostaglandin D2(PGD2) is another prostaglandin produced by hematopoietic and lipoprotein prostaglandin D synthase (hPGDS and lPGDS) acting on prostaglandin H2(PGH2). In addition, the two have different receptors and different areas of study. PGE2: Mainly studies gastrointestinal smooth muscle PGD2: Studies allergic diseases such as asthma

We recommend that you refer to the cell sample treatment in the instructions instead of using 0.1M HCl for cell lysis. In theory, 0.1M hydrochloric acid can only change the permeability of cells and cannot lyse cells. At the same time, the introduction of strong acids will lead to the degeneration of proteins, which will affect the binding of antigens and antibodies, and change the pH value of the ELISA experimental system, and ultimately affect the experimental results.

Platelet has a specific morphological structure and biochemical composition, and has a relatively constant number in normal blood. It plays an important role in physiological and pathological processes such as hemostasis, wound healing, inflammation, thrombosis and organ transplantation rejection. Platelets are found only in mammalian blood. There is no fasting requirement when we test the serum plasma of normal rats for thrombatin. According to the situation in the literature, the thrombopoietin in serum plasma of rats was generally detected 24h after administration, and the requirement of fasting in rats was not mentioned. It is suggested that you can make reference selection according to the experimental purpose and literature.

The medium containing phenol red may have an effect on the detection of testosterone. Phenol red is used in the medium as an indicator of PH: red when neutral, yellow when acidic, and purple when alkaline. Studies have shown that phenol red can mimic the effects of sterol hormones (especially estrogen). To avoid sterol reactions, cultured cells, especially mammalian cells, are cultured without phenol red. Introduce a tip: when the medium is packaged, leave a tube with phenol red and put it in the incubator to balance (you can see the change in PH value, and you can see whether the medium is polluted). Put in the incubator before culture for balanced use (can avoid the use of phenol red during culture).

According to the ApoE gene model, the synthesis of ApoE is controlled by three alleles located at a single gene locus, namely E2, E3 and E4. Each allele corresponds to a major isomer to produce three homozygotes (E2/2, E3/3, E4/4) and three heterozygotes (E2/3, E2/4, E3/4), a total of six common phenotypes. ApoE 3/4 is at the gene level, and ELISA kit detects the APOE content at the protein level, which cannot reflect the expression of APOE3/4 at the gene level.

PGI2 is extremely unstable, with a half-life of 14.5 min in an aqueous solution with a pH of 7.48. In a neutral medium, it can also be hydrolyzed to 6-ketone PGFla. The kit design is PGI2, but because PGI2 is relatively unstable in biological fluid samples, the antibody we designed also cross-reacts to its metabolite 6-keto PGFla, aiming to react the total amount of PGI2 by detecting the content of 6-keto PGFla and PGI2.

Cytochrome-c: the most abundant and stable Cytochrome. Participate in energy transfer; Cytochrome P450 aromatase: A cytochrome P450 monooxygenase that catalyzes the conversion of C19 androgens, androgen-4-ene-3, 17-dione (androstenedione) and testosterone to C18 estrogens, estrone and estradiol, respectively.

These two items are different, and E-EL-H0835 detects 1196-1218aa of Human CTXⅠ; E-EL-H0960 detects 1207-1214aa of Human β-CTx. In addition, the functions of the two are different. CTXⅠ is the degradation indicator of type I collagen. β-CTx was the evaluation index of bone reresorption.

The sC5b-9 kit detects the total, both active and inactive forms. MAC is present on cells, but when the multifunctional glycoprotein S protein (vitronectin) binds to the liquid phase of C5b9, it forms a complex that cannot attach to cells, called SC5b9. SC5b-9 is a membrane-attacking complex present in plasma. At abnormally elevated concentrations, SC5B-9 exhibits cytotoxicity, interacts with cytoskeletal components or membrane proteins to produce non-lethal effects on cells, and plays an important role in the pathological process of certain diseases. This kit measures the concentration of sC5b-9, which is generally used to study disease models related to sC5b-9 indicators, and can show changes in concentration between groups, but cannot represent the formation process of MAC on cells.

The interleukin (IL)-1 family of cytokines is associated with immune response and inflammation. It consists of the following 11 different molecular forms: Intercellular IL-1α (IL-1F1), extracellular IL-1β (IL-1F2), IL-1 receptor antagonist (IL-1Ra, IL-1F3), And IL-18 (IL-1F4), IL-33 (IL-1F11), IL-36α (IL-1F6), IL-36β (IL-1F8), IL-36γ (IL-1F9), IL-36Ra (IL-1F5), IL-37 (IL-1F7), and IL-38 (L-1F10). One of the most important pro-inflammatory cytokines is IL-1β. It is primarily an inactive 31 kDa precursor produced by monocytes and macrophages, interleukin-1β (proIL-1β), which under the action of cysteine protease IL-1 convertase (ICE) produces a mature and biologically active 17.5kDa protein IL-1β.The E-EL-M0037 kit detects mature IL-1β.

The Liver function-related indicators we have ELISA kits are here for your reference: E-EL-H0556 Human LDHA(Lactate Dehydrogenase A) ELISA Kit E-EL-H2598 Human ALPL(Alkaline Phosphatase, Liver/Bone/Kidney) ELISA Kit E-EL-H6105 Human ALB(Albumin) ELISA Kit E-EL-0076 Bb(Bilirubin) ELISA Kit

The detection antibodies in our ELISA kits are all HRP-based. Currently, there are no kits available for testing red blood cell lysate. For small amounts of hemoglobin, consider increasing the number of washing steps by 1-2 during the first plate washing step to reduce interference. However, besides hemoglobin, substances such as endogenous HRP enzymes released during the process of red blood cell lysis can also catalyze the substrate, so we still do not recommend testing with such samples.

Tissue samples may contain endogenous or exogenous proteases during processing, leading to degradation of extracted proteins. Therefore, it's necessary to add protease inhibitors during processing to ensure the integrity of target proteins. If customers can keep samples cold and handle them quickly during processing, omitting the protease inhibitor may not have a significant effect. After preparation, samples should be tested promptly or immediately aliquoted and frozen at -20°C or -80°C.

TGF-β1 exhibits high sequence conservation, and its structure varies minimally among different species. Therefore, our kit can achieve universal detection.

After the collection with the swab, elute with 500μl PBS, centrifuge at 5000×g for 10 minutes (if the sample remains turbid, try centrifuging at 10000×g), then collect the supernatant for testing.

6-sulfatoxymelatonin (6-SMT) is a major metabolite of melatonin. While the melatonin ELISA kit theoretically may cross-react with 6-SMT to some extent, we do not recommend using it to detect this marker.

Circulating leptin refers to leptin levels, with "circulating" describing the fluctuation of leptin levels.

Currently, our ELISA kits are only suitable for animal samples, and we do not have kits for testing plant/microbial samples.

No, the detection system of our kits requires strict adherence to the specified sample volume to ensure accurate detection. If the sample volume is insufficient, consider diluting appropriately, but first conduct a pre-experiment to confirm the suitable dilution factor.

As long as the samples and reagents used during the activation step are consistent with the proportions in the manual, it should fine.

Our IL-23 kit is designed to detect the complete heterodimeric IL-23 protein. It may not detect the monomeric IL-23P19 subunit.

Our ELISA kits have not been validated for compatibility with automated analyzers. The provided instructions are for manual operation. Customers may validate them on their own if needed.

To ensure temperature fluctuations during incubation stay within 1°C, it's recommended to use an incubator. If an incubator is not available, a water bath may be used, but precautions should be taken to avoid contaminating the plate with water. Using a shaker, especially one with vibration, for incubation is not recommended.

Glucagon-like peptide-1 (GLP-1) is a peptide hormone with a relatively short half-life due to rapid degradation by dipeptidyl peptidase-4 (DPP-4) and neutral endopeptidase (NEP 24.11). Only a small fraction of GLP-1 will fully enter circulation. Our GLP-1 kit is designed to detect intact GLP-1 protein and may not detect its metabolites. Although some customers add sitagliptin (DPP-4 inhibitor) and trifluoroacetic acid to samples to prevent GLP-1 degradation, we do not recommend adding organic agents to samples as they may interfere with ELISA detection.

Under physiological conditions, α-syn exists as unfolded monomers, in equilibrium with membrane-bound species that promote SNARE-complex assembly and tetramers that can resist abnormal aggregation. When the balance between α-syn generation and clearance is disrupted, the monomers aggregate to form oligomers, including on-pathway oligomers and off-pathway oligomers. On-pathway oligomers tend to form protofibrils, and eventually fibrils. Other oligomers that cannot form amyloid fibrils are called off-pathway oligomers. E-EL-H0983 Human SNCα ELISA Kit is for monomer Alpha synuclein, other forms of Alpha synuclein have not been verified whether can be detected.

VCAM-1 is a transmembrane protein that can be partially hydrolyzed, allowing it to enter the bloodstream. The portion of VCAM-1 that enters the bloodstream is referred to as soluble VCAM-1 (sVCAM-1). E-EL-H5587 Human VCAM-1 kit detects total VCAM-1, including membrane-bound form and soluble form.

Hair sample preparation method: Wash hair samples with methanol by adding 5 mL of HPLC-grade methanol to each sample, rotating for 3 minutes, then decanting excess methanol and rinsing hair twice. After washing, place the hair samples on aluminum foil, dry for 3 days in a protective cap. Weigh the dried hair samples and transfer them to 2ml polypropylene tubes containing stainless steel grinding beads. Place the tubes containing hair and beads in a bead beater, grind each sample for 2 minutes to produce powder. After grinding, add 1.5 mL of methanol to the tubes containing hair powder. Rotate samples slowly for 24 hours to extract steroids. Centrifuge at 10000 g for 4 minutes, transfer 0.6 mL of methanol supernatant containing steroids to new 1.5 mL microcentrifuge tubes. Dry the samples in a protective hood for 2-3 days to evaporate the methanol. Dilute the dried extract with 0.4 mL dilution buffer from the kit for detection.

Hepcidin is a cysteine-rich antimicrobial peptide synthesized and secreted by the liver. It is highly expressed during immune responses and plays a negative regulatory role in iron homeostasis within the body. As a mature peptide consisting of 25 amino acids, hepcidin binds to membrane iron transport proteins, inducing their internalization and degradation, thereby controlling iron absorption and release to maintain plasma iron levels within the normal range. Hepcidin-25, primarily produced in the liver, is generated by proteolytic cleavage of the C-terminus of prohepcidin. These 25 amino acids represent the active form of hepcidin, capable of executing its biological functions. Subsequently, the N-terminus of hepcidin-25 undergoes conversion into smaller peptides (approximately 20~24 amino acids), which exhibit lower activity and accumulate in urine. In summary, the main difference between hepcidin and hepcidin-25 lies in their origin and form. Hepcidin is the unmodified precursor peptide, whereas hepcidin-25 is a specific fragment of hepcidin, possessing distinct biological activity. Functionally, both participate in iron regulation, but hepcidin may be involved in a broader range of biological processes.

The ICAM family consists of five members, designated ICAM-1 to ICAM-5. They are known to bind to leucocyte integrins CD11/CD18 such as LFA-1 and Macrophage-1 antigen, during inflammation and in immune responses. ICAM-1 which consists of five Ig-like domains, is found on the surface of leukocytes, endothelial cells and various other cells, and can be up-regulated byseveral proinflammatorycytokines. Intercellular adhesion molecule-4 (ICAM-4, LW blood group antigen), a member of the immunoglobulin superfamily expressed on red cells, contains two immunoglobulin domains of which the first domain is 30% identical to the first domains of ICAM-1,-2 and -3. Although both ICAM-1 and ICAM-4 are members of the immunoglobulin superfamily, they exhibit significant differences in cell adhesion, immune regulation, and specific biological functions. ICAM-1 primarily functions in leukocyte recruitment and inflammatory responses, while ICAM-4 is more involved in interactions between leukocytes and red blood cells, as well as in the activation and regulation of immune cells.

the kit detects the 50kDa active heparanase subunit

the kit detects total Thyroglobulin.

This kit is designed to measure full length complement C5.

sLOX-1 refers to the soluble form of LOX-1, which contains the amino acid sequence of LOX-1. Our E-EL-H1635c kit utilizes the immunogen of sLOX-1, allowing it to detect sLOX-1 in secreted samples (such as serum or plasma) as well as the membrane protein form in tissue and cell lysates.

The protein conformation of the inactivated sample has changed, which may affect antigen-antibody binding, so we cannot guarantee ELISA results. Customers are advised to use freshly collected samples for ELISA testing.

E-EL-H1478 Human PTHrP ELISA(Uniprot: P12272) is suitable for the detection of natural proteins. Abaloparatide is a synthetic 34-amino acid polypeptide that is an analogue of parathyroid hormone-related protein (PTHrP). However, it is necessary to consider that the difference in spatial conformation may lead to unrecognition, So the kit may not be able to detect Abaloparatide.

At present, hamster samples have not been verified for detection in mouse kits, and it is not a same species, so testing is not recommended.

A standard curve is not a straight line (a curve that resembles a line). It is recommended to use Origin software or other software with 4-PL (four-parameter logistic) function model to fit the standard curve. The 4-PL fitting method can reflect the linear relationship between concentration and absorbance more accurately, so as to obtain the concentration value of the substance to be measured in the sample more accurately.

Pulmonary surfactant associated protein (SP) can be divided into SP-A, SP-B, SP-C and SP-D. SP-A is a Pulmonary Surfactant (PS). The SP-A gene contains SP-A1 and SP-A2; SP-A is mostly derived from the transcription of SP-A1.

E-EL-M3009 Mouse Aβ1-40(Amyloid Beta 1-40) ELISA Kit detects mouse Aβ1-40, The E-EL-M3010 Mouse Aβ1-42(Amyloid Beta 1-42) ELISA Kit detected mouse Aβ1-42, and the content of Aβ1-40 was generally higher than Aβ1-42, but Aβ1-42 was closely related to the occurrence of AD disease. The Aβ monomer itself is soluble, and Aβ can aggregate into oligomers or fibers, both of which are insoluble. Thus, in the brains of AD patients, Aβ comes in three forms: soluble monomers, oligomers, and insoluble fibers. At present, most scholars believe that the neurotoxicity of Aβ is mainly manifested by its Oligomers.

It is recommended to use PBS, RIPA has an impact on the detection of some indicators, try to avoid using it. Depending on whether the protein you want to study is on the membrane, in the nucleus or in the cytoplasm, RIPA lysate is less efficient for extracting proteins on the membrane and in the nucleus. If that's the case, buy a specialized cell structure protein extraction kit. When ELISA detects cytokines, it is necessary to select the corresponding lysate to treat the sample according to the different cytokines detected.

TGF-β1 is usually present in an inactive form in biological samples and must be activated before TGF-β1 activity can be detected. The detection of serum, plasma, cell supernatant and other secretory samples requires activation treatment. Intracellular samples such as tissue homogenate supernatant can be detected without activation.

It can be used, but cell culture requires a sterile environment, ELISA does not need to be sterile, we recommend that customers try not to use this instrument, to avoid doing other experiments such as cell culture caused by pollution, you can choose a conventional oven or water bath

According to the different bottom, it is divided into flat bottom, U-shaped bottom, V-shaped bottom and so on. The index of refraction of the flat bottom is low, which is suitable for detection in the enzyme reader. According to the color can be divided into transparent, black, white. Transparent is commonly used for the most general enzyme-linked immunoassay.

E-EL-E605 SARS-CoV-2 Spike Protein S1 RBD ELISA Kit, Immunogenic sequence (AA: 319-541 Accession: P0DTC2), the S1 RBD protein identified by our kit is partially inconsistent with the customer's recombinant protein S1 415-636, and due to the difference in spatial conformation of the recombinant protein, the customer's protein is not sure to be recognized.

We haven't verified human hair samples internally, so we recommend a preliminary test. Treatment method :ELISA was used to determine hair cortisol. The extraction process involves successive incubation in methanol and acetone, repeated twice

The sample does not need to dilute into a uniform concentration and then the sample is loaded. The tissue sample can be made into 10% tissue homogenate, and then the total concentration is detected by BCA method, and then the ELISA test is performed. The concentration of target protein detected by ELISA/the concentration of total tissue protein can be obtained in the tissue sample (pg/mg prot).

When cracking MCM7 cells, customers can directly pre-cool 0.01M PBS and trypsin according to the instructions, but pay attention to ensure the cell growth state and ensure that the number of cells reaches 10^6

It will have an impact. Because its aqueous solution can denature the protein, it will affect the HRP activity and interfere with the overall detection, so it is not suitable for ELISA method. The addition of sodium azide is not recommended, but customers should take care to avoid contamination during urine collection.

E-EL-0009 FA/VB9 is a universal ELISA kit that mainly detects folic acid content in biological liquids of all species (mainly human, rat and mouse). We have not verified folic acid in feed internally, but at present, the content of folic acid in feed is mostly detected by microbial detection methods

E-UNEL-H0163 Uncoated Human IL-27(Interleukin 27) ELISA Kit IL-27, Both p28 and EBI3 subunits can be detected.

The antigen is diluted with coated solution, the first antibody is diluted with universal sample diluent or ready-to-use biotinized antibody diluent, and the second antibody is diluted with ready-to-use HRP enzyme conjugate.