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FAQs

In order to provide better customer support, we have published Answers to the most Frequently Asked Questions (FAQs) about Elabscience® products.

  • 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.
  • Prepared sample solutions (sample solutions for which the sample pre-treatment process has been completed according to the instructions) can be stored for about 1 month at 4°C under sealed conditions.
  • 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.
  • 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.
  • 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
  • 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 substances detected by food safety test kits mostly belong to chemical substances, which are theoretically not limited by biological species and sample types, as long as the instructions can provide corresponding sample pre-treatment. However, certain indicators are extracted differently in different species or types of samples. Therefore, please refer to the manual or contact technical support for details.
  • 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.
  • It is not recommended to perform any processing on the standards of the food safety test kits because the gradient standard concentrations are designed according to the characteristics of the test kits. Processed standards may not work with the corresponding test kits and test results cannot be guaranteed.
  • ELISA readers that can be set to 450 nm will meet the needs of the assay. It is preferable if the wavelength can also be set to 630 nm. No other requirements.
  • Article number starting with E-TO/FS-C (e.g., 50T): 50T indicates that the kit can be tested 50 times. The maximum number of samples that can be tested without duplication is 50. Article number starting with E-TO/FS-E (e.g., 96T): Maximum of 42 samples if both the standard and sample are duplicated (The instructions recommend duplicating both samples and standards). Maximum of 84 samples if only the standard is duplicated. Maximum of 90 samples if neither the standard nor the sample is duplicated.
  • Each ELISA plate consists of 8 wells * 12 strips, which can be disassembled. Unused strips need to be placed in an aluminum foil bag and sealed at 4 ℃.
  • This kit can only be used to detect M1, unfortunately we do not have a kit for M2. Aflatoxin M1 is a metabolite of aflatoxin B1, which is the most toxic and abundant toxin, and is therefore required by regulations to be tested for aflatoxin M1 in dairy products.
  • E-TO-E028 kit is suitable for sample types such as herbs, while the E-TO-E006 is suitable for testing grains and feeds.
  • There are currently two types of food safety kits, qualitative and quantitative. Please refer to the "Intended Use" section on the product detail page for the different product result types.
  • 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.
  • The preservative in the Food Safety Kit is Proclin 300 at a concentration of <0.1%.
  • 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.
  • 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.
  • In addition to the aluminum foil bag that has been vacuum-sealed, an empty aluminum foil bag will be included with the kit. Customers can seal and store the removed aluminum foil strip in a new aluminum foil bag and store the components according to the instructions. The plate sealer is a sticky film used to seal the plate holes in the incubation stage, which can control and reduce the evaporation of water in the incubation stage and better maintain the uniform heating of the whole plate, minimizing the influence of edge effect on the test results.
  • The purpose of the pre-test is: ① to determine whether the kit is suitable for your sample detection, so as to avoid the waste of kits and samples; ② To help you get familiar with the operating process of the kit, especially the customers who use the ELISA kit for the first time/change the experimental brand; ③ Determine whether the sample is diluted or not and whether the dilution ratio is suitable for the determination of this kit and confirm the optimal sample dilution information; ④ Help to understand the experimental phenomena or problems that may occur during the experiment, so as to make timely adjustments; Specific methods: Before the formal test, 2-3 samples with large differences are selected to dilute the samples with different concentrations, and then pre-test is conducted according to the experimental procedures in the instructions. According to the results of the pre-test, the optimal dilution ratio of the samples is determined combined with the detection range of the kit.
  • In order to ensure the accuracy of the experimental results, we suggest that both standards and samples should be tested in duplicate. Of course, ELISA experiments do not necessarily have to be repeated /3 repeated Wells, customers can set the repeat or not according to their own needs.
  • Tissue sample: After finishing tissue grinding, place it at -80℃ for 1h/ liquid nitrogen for 0.5h, and then gently shake it in a water bath at 30℃ to melt it quickly. Repeat this operation 1-2 times. Cell sample: Repeat the above freeze-thaw operation 2-3 times. If it is a membrane protein, it can be appropriately sonicated, but the temperature and frequency of ultrasound need to be controlled. It is recommended to add protease inhibitors to the sample in advance. PMSF(Cat.E-EL-SR002) is generally recommended.
  • Traditional Competion Method: about 2.0 h; Traditiona three-steps Sandwich method: about 3.5h; QuicKey ELISA: about 2.5h; QuicKey Pro ELISA: about 1.5h.
  • Using ultrasonic cell crusher, ultrasonic treatment of the suspension to lyse the cells (reference: Soniprep150 ultrasonic generator, ultrasonic treatment of 30s at an amplitude of 14μm, cell fragmentation; Or use an ultrasonic crusher, 200W, 2s/ times, gap 3s, total time 3-5min or 400 amp, 5s/ times, gap 10s, repeated 3-5 times), and then centrifuge at 2 to 8℃ at 1500×g for 10min, remove the cell debris, collect the supernatant. Attention should be paid to temperature during ultrasound.
  • The standard curve on the manual is an indicator curve, mainly used to show the shape of the standard curve after fitting and the quality control range of the highest/lowest OD value, you can not directly use. In addition, due to the influence of experimental operation, experimental environment, instrument parameter setting and other factors, the OD value of your actual standard curve may not be completely consistent with the instructions (overall high or low). In this case, it is recommended to control the first 4 blue wells in the color development stage with obvious color gradient and the maximum OD value of the standard curve above 1.2. If the correlation coefficient of the standard tune is above 0.99, it can be used as an effective standard curve.
  • The detection range of the kit is not the same as the concentration range of the substance to be measured in the sample. It is recommended to estimate the concentration of the substance to be measured in the sample through relevant literature before the experiment and determine the actual concentration of the sample through pre-experiment. If it is a routine sample type, you can consult ELISA technical support to obtain the recommended dilution of the sample and schedule pre-laboratory testing. If the concentration of the substance to be measured in the sample is too high or too low, dilute or concentrate the sample appropriately. If the concentration of analyte in the sample is much lower than the minimum detection line of the kit, it is recommended to choose a kit with higher sensitivity for detection.
  • It is recommended that customers do technical repetition, on the one hand can confirm the operation method, on the other hand can verify and improve the accuracy of the experimental results. A positive control in an ELISA test can be considered the standard product. Negative control is a blank matrix or a matrix solution with known low concentration that has homology and homogeneity with the object to be picked up, which is generally difficult to obtain, and can be set as a negative control if available. The routine is to set a blank control, that is, a sample diluent.
  • Neither can be reduced. The sample volume of each step should be strictly in accordance with the instructions, otherwise the experimental system will be changed, and the results will be inaccurate. If the customer really does not have enough sample volume, you can consult the technology to confirm whether the sample can be diluted, and judge the sample concentration through pre-experiment Degree situation. If the volume of the reagent is not enough, the number of holes to be tested can only be reduced according to the actual volume, and the detection can not be diluted.
  • Different sample types of matrix are different, in order to reduce the influence of the matrix itself and improve the accuracy of routine sample measurement, usually set different systems of ELISA kits, and display with different product numbers. In addition, the concentration of some indicators varies greatly between different samples, so different products are used to meet customers' needs for ease of operation.
  • If your test sample needs dilution, refer to the dilution method as follows: For 100 fold dilution: One-step dilution. Add 5 μL sample to 495 μL sample diluent toyield 100 fold dilution. For 1000 fold dilution: Two-step dilution. Add 5 μL sample to 95 μL sample diluent toyield 20 fold dilution, then add 5 μL 20 fold diluted sample to 245 μL sample diluent,after this, the neat sample has been diluted at 1000 fold successfully. For 100000 fold dilution: Three-step dilution. Add 5 μL sample to 195 μL sample diluentto yield 40 fold dilution, then add 5 μL 40 fold diluted sample to 245 μL sample diluentto yield 50 fold dilution, and finally add 5 μL 2000 fold diluted sample to 245 μL samplediluent, after this, the neat sample has been diluted at 100000 fold successfully. The amount of liquid taken at each dilution step is not less than 3μL, and the dilution ratio is not more than 100 times. Each dilution should be mixed evenly to avoid bubbles
  • There are four specifications of 96T/48T/24T/96T*5. Among them, 24T is the trial size.
  • At present, the species detected by our ELISA kit are mainly human, mouse, rat and a small number of targets involve special species such as monkey, rabbit, pig and chicken. Kits with the name of a particular species (such as human) are specific to that species. If no species is specified in the manual, the kit is generic within the conventional universal species. If the species tested is special, it is recommended to confirm the suitability of the sample with technical support first.
  • angiotensin II [Homo sapiens]GenBank in NCBI: CAA77513.1 shows that the protein with fixed number "P30556" of Uniprot is "Type-1 angiotensin II receptor", which is a Type 1 receptor of angiotensin II and not the same protein as angiotensin II. The Uniprot database is composed of Swiss-Prot, TrEMBL and PIR-PSD sub-databases. The data are mainly from the whole gene protein sequences obtained after genome sequencing of each species, and contain a lot of protein and its function information from the literature. NCBI(US National Center for Biotechnology Information) data resources from several major DNA databases around the world, including the Japanese DNA database DDBJ, the European Molecular Biology Laboratory database EMBL and several other well-known scientific research institutions, the two sources of information may be inconsistent, sometimes in terms of the name is not strictly audited, there may be a certain discrepancy.