| Description | Fructokinase (FK, EC 2.7.1.4) regulates the interconversion between sucrose and starch and is involved in modulating plant metabolism and growth development. Fructokinase (FK) phosphorylates fructose to generate fructose-6-phosphate. This product is subsequently acted upon by a series of composite Fructokinase (FK, EC 2.7.1.4) regulates the interconversion between sucrose and starch and is involved in modulating plant metabolism and growth development. Fructokinase (FK) phosphorylates fructose to generate fructose-6-phosphate. This product is subsequently acted upon by a series of composite enzymes, reducing NADP+ to NADPH. The enzyme activity of fructokinase is determined by measuring the rate of increase in NADPH absorbance at 340 nm.Component50TStorageExtraction Buffer60 mL2-8℃Reagent 140 mL2-8℃Reagent 21EA-20℃Reagent 31EA-20℃Reagent 41EA2-8℃Reagent 51EA2-8℃Reagent PreparationReagent 2 (Powder, 1 vial):Before use, centrifuge at 8000 g, 4°C for 2 min to collect the powder at the bottom.Add 1.7 mL of distilled water to dissolve.The storage period is the same as the kit's expiry date.Reagent 3 (Liquid, 1 vial):Before use, centrifuge at 8000 g, 4°C for 2 min to collect the liquid at the bottom.Add 1.7 mL of distilled water to dissolve.The storage period is the same as the kit's expiry date.Reagent 4 (Powder, 1 vial):Before opening, ensure the powder is at the bottom of the vial.Add 17 mL of Reagent 1 to dissolve.The storage period is the same as the kit's expiry date.Reagent 5 (Liquid, 1 vial):Before use, centrifuge at 8000 g, 4°C for 2 min to collect the liquid at the bottom.Add 1.7 mL of distilled water to dissolve.The storage period is the same as the kit's expiry date.User-Prepared Instruments & MaterialsMortar (homogenizer), ice bucket (ice maker), benchtop centrifuge, adjustable pipettes, water bath (oven, incubator, metal bath), 1 ml quartz cuvette, centrifuge tubes, UV spectrophotometer, distilled water (deionized water or ultrapure water is acceptable).Sample Extraction1. Tissue Samples: Weigh approximately 0.1 g of tissue, add 1 mL of Extraction Buffer, and homogenize on ice. Centrifuge at 12000 rpm, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.Note: If increasing the sample amount, use a ratio of 1:5 to 1:10 (tissue weight (g) : Extraction Buffer volume (mL)) for extraction.2. Bacterial/Cell Samples: Collect bacteria or cells into a centrifuge tube by centrifugation and discard the supernatant. Take 5 million bacteria or cells, add 1 mL of Extraction Buffer, and disrupt using ultrasound on ice (power 20% or 200 W, ultrasonicate for 3 s, interval 10 s, repeat 30 times). Centrifuge at 12000 rpm, 4°C for 10 minutes. Collect the supernatant and keep it on ice for assay.Note: If increasing the sample amount, use a ratio of 500-1000 (x10⁴ cells) : 1 (mL Extraction Buffer) for extraction.3. Liquid Samples: Detect directly. If the sample is turbid, centrifuge and use the supernatant for detection.Assay Procedure1. Preheat the UV spectrophotometer for at least 30 minutes. Set the wavelength to 340 nm. Zero the instrument with distilled water.2. Thaw all reagents to room temperature (25°C).3. In a 1 mL quartz cuvette, add sequentially:Reagent (µL)Test CuvetteSample70Reagent 230Reagent 3430Reagent 4580Mix well and incubate at 37°C for 5 minutes. 4. Add:Reagent (µL)Test CuvetteReagent 5305. Mix well. Immediately read the absorbance at 340 nm (A1), and then read again after 15 minutes (A2). Calculate ΔA = A2 - A1.Notes:1. If ΔA is close to zero, the reaction time can be appropriately extended to 30 minutes or longer before reading A2; or the sample volume V1 can be increased appropriately (with a corresponding decrease in Reagent 4 volume). The modified reaction time (T) and sample volume (V1) must be substituted into the calculation formula.2. If the initial absorbance A1 is too high (e.g., >2, as in deeply pigmented plant leaves), appropriately reduce the sample volume V1 (with a corresponding increase in Reagent 4 volume). The modified V1 must be substituted into the calculation formula. Alternatively, add a small amount of activated carbon to the sample, mix, let stand for 5 min, then centrifuge at 12000 rpm, 4°C for 10 min, and use the supernatant for detection.3. If the increasing trend is unstable, read the absorbance every 10 seconds and select a linear increasing period for calculation. The corresponding ΔA value should be substituted into the calculation formula.FK Activity Calculation1. Based on Sample Protein Concentration:Unit Definition: One unit of enzyme activity is defined as the generation of 1 nmol NADPH per minute per mg of protein.Formula:FK (nmol/min/mg prot) = [ΔA ÷ (ε × d) × V2 × 10⁹] ÷ (V1 × Cpr) ÷ T = 113.3 × ΔA ÷ Cpr2. Based on Sample Fresh Weight:Unit Definition: One unit of enzyme activity is defined as the generation of 1 nmol NADPH per minute per gram of fresh tissue.Formula:FK (nmol/min/g fresh weight) = [ΔA ÷ (ε × d) × V2 × 10⁹] ÷ (W × V1 ÷ V) ÷ T = 113.3 × ΔA ÷ W3. Based on Bacterial/Cell Density:Unit Definition: One unit of enzyme activity is defined as the generation of 1 nmol NADPH per minute per 10⁴ bacteria/cells.Formula:FK (nmol/min/10⁴ cell) = [ΔA ÷ (ε × d) × V2 × 10⁹] ÷ (500 × V1 ÷ V) ÷ T = 0.227 × ΔA4. Based on Liquid Volume:Unit Definition: One unit of enzyme activity is defined as the generation of 1 nmol NADPH per minute per mL of liquid.Formula:FK (nmol/min/mL) = [ΔA ÷ (ε × d) × V2 × 10⁹] ÷ V1 ÷ T = 113.3 × ΔAParameter Description:ε: NADPH molar extinction coefficient, 6.22 × 10³ L/mol/cmd: Light path of the 1 mL quartz cuvette, 1 cmV: Volume of Extraction Buffer added, 1 mLV1: Volume of sample supernatant added, 0.07 mLV2: Total reaction volume, 0.74 mL = 7.4 × 10⁻⁴ LT: Reaction time, 15 minW: Sample mass, g500: Cell number, in units of 10⁴Cpr: Protein concentration of the supernatant, mg/mL; Aladdin BCA Protein Quantification Kit (B665595) or Ready-to-Use BCA Protein Quantification Kit (R1491648) are recommended.PrecautionsIt is recommended to first select 1-3 samples with significant differences (e.g., different types or groups) for preliminary experiments to familiarize yourself with the procedure. Determine or adjust the sample concentration based on the preliminary results to prevent unnecessary waste of samples or reagents... Read More | D-Lactate, typically present in the bloodstream at nanomolar concentrations, is produced by an intestinal source or via the methylglyoxal pathway. In mammals, D-Lactate metabolism requires D-Lactate hydrogenase and is metabolized slowly, thus an increase in blood concentration levels can lead to D-Lactate, typically present in the bloodstream at nanomolar concentrations, is produced by an intestinal source or via the methylglyoxal pathway. In mammals, D-Lactate metabolism requires D-Lactate hydrogenase and is metabolized slowly, thus an increase in blood concentration levels can lead to acidemia and acidosis. The severity of this D-lactic acidosis can be associated with neurotoxic symptoms. Significant D-Lactate accumulations in the body can also be related to impaired metabolism and excretion.D-Lactate Colorimetric Assay kit has been used to determine the stereospecificity of lactate produced.Suitability: Suitable for use with samples of serum, plasma, cells, culture and fermentation media.Principle: In this assay, D-Lactate is specifically oxidized by D-Lactate hydrogenase and generates a proportional colorimetric product measured at 450 nm. The useful concentration range in samples is 0.1-10 mM D-Lactate... Read More | Inquire | Product contentN666081Component50 TStorageN666081ANc-Buffer A50 mL2-8℃N666081BNc-Buffer B3 mL2-8℃N666081CNc-Buffer C25 mL2-8℃N666081DProtease Inhibitor Cocktail750 µL-20℃. Avoid freeze/thaw cycle.ProductsThe Nc-Nucleus/Plasma Protein Extraction Kit is a simple and rapid Product contentN666081Component50 TStorageN666081ANc-Buffer A50 mL2-8℃N666081BNc-Buffer B3 mL2-8℃N666081CNc-Buffer C25 mL2-8℃N666081DProtease Inhibitor Cocktail750 µL-20℃. Avoid freeze/thaw cycle.ProductsThe Nc-Nucleus/Plasma Protein Extraction Kit is a simple and rapid method for extracting nucleus and plasma proteins from mammalian cells and tissues, and the extracted proteins remain biologically active. The kit first cleaves the cell membrane and releases plasma proteins using the plasma protein extraction reagent, and then centrifuges the nucleus to obtain a nucleus precipitate. Finally, the nuclear proteins are extracted by the nuclear protein extraction reagent. The extracted nuclear and plasma proteins are of high purity, effectively avoiding cross-contamination of nuclear and plasma proteins, and can be used for subsequent operations such as Western, Gel Shift, reporter gene detection and enzyme activity determination.Caveat1. If phosphorylated proteins are to be extracted, add a phosphatase inhibitor to the extraction reagent.2. All sample handling should be done on ice.3. The amount of reagents can be adjusted according to the specific experimental situation to ensure that the ratio of each reagent used is Nc-Buffer A:Nc-Buffer B:Nc-Buffer C = 100:5.5:50.4. Higher speeds can be used for centrifugation.ProcedureI Extraction of cytoplasmic and cytosolic proteins from cells1. Please remove the extraction reagents Nc-Buffer A and Nc-Buffer C for pre-cooling before protein extraction.2. Collect the cells and count them. Centrifuge to remove supernatant.3. 1×107 cells were added with 1 ml of Nc-Buffer A (added to Protease Inhibitor Cocktail at a ratio of 1:99 within 2-3 minutes prior to protein pumping), vortexed for 5 seconds to mix well, and incubated on ice for 20 minutes.Note: The characteristics of various cells are different, and the amount of Nc-Buffer A needs to be adjusted according to the characteristics of different cells. If the protein concentration is small, reduce the amount of Nc-Buffer A and subsequent Nc-Buffer B and Nc-Buffer C proportionally.4. Add 55 µl of Nc-Buffer B, vortex for 5 seconds to mix thoroughly, and incubate on ice for 1 minute.5. Centrifuge at 12,000 rpm (~13,400 x g) for 15 minutes at 4°C, collect the supernatant (as clean as possible) into a new centrifuge tube and store at -20°C (this extract is cytoplasmic protein).6. Add 500 µl of Nc-Buffer C (add Protease Inhibitor Cocktail at a ratio of 1:99 before use) to the precipitate obtained in the previous step, vortex for 5 seconds to mix thoroughly, resuspend the precipitate and incubate on ice for 40 minutes, vortexing and mixing at 10-minute intervals for about 15-30 seconds each time.7. Centrifuge at 12,000 rpm for 15 minutes at 4°C, collect the supernatant (as clean as possible) into a new centrifuge tube and store at -20°C (this extract is for cytosolic proteins).II Extraction of cytoplasmic and cytosolic proteins from tissues1. Sampling and preservation of tissues.2. Remove the extraction reagents Nc-Buffer A and Nc-Buffer C for pre-cooling before protein extraction.3. Weigh the tissue and add 1 ml of Nc-Buffer A per 100 mg of tissue (add Protease Inhibitor Cocktail 2-3 minutes before protein extraction at a ratio of 1:99), homogenize well on ice with a homogenizer, and incubate on ice for 20 minutes.Note: The characteristics of various tissues are different, and the amount of Nc-Buffer A needs to be adjusted according to different tissues. If the protein concentration is small, reduce the amount of Nc-Buffer A and subsequent Nc-Buffer B and Nc-Buffer C proportionally.4. Add 55 µl of Nc-Buffer B, vortex for 5 seconds to mix thoroughly, and place on ice for 1 minute of incubation.5. Centrifuge at 12,000 rpm for 15 minutes at 4°C, collect the supernatant (as clean as possible) into a new centrifuge tube and store at -20°C (this extract is cytoplasmic protein).6. Add 500 µl of Nc-Buffer C (add Protease Inhibitor Cocktail at a ratio of 1:99 before use) to the precipitate obtained in the previous step, vortex for 5 seconds to mix thoroughly, resuspend the precipitate and incubate on ice for 40 minutes, vortexing and mixing at 10-minute intervals at, each time for about 15-30 seconds.7. Centrifuge at 12,000 rpm for 15 minutes at 4°C, collect the supernatant (as clean as possible) into a new centrifuge tube and store at -20°C (this extract is cytosolic protein)... Read More | Inquire |