Casein, FITC-conjugated
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Molecular weight | N/A |
Solvent | Water |
Correction Factor (280 nm) | 0.35 |
Extinction coefficient (cm -1 M -1) | 73000 |
Excitation (nm) | 491 |
Emission (nm) | 516 |
Quantum yield | 0.92 |
H-phrase | H303, H313, H333 |
Hazard symbol | XN |
Intended use | Research Use Only (RUO) |
R-phrase | R20, R21, R22 |
Storage | Freeze (< -15 °C); Minimize light exposure |
UNSPSC | 12352200 |
Overview | ![]() ![]() |
Molecular weight N/A | Correction Factor (280 nm) 0.35 | Extinction coefficient (cm -1 M -1) 73000 | Excitation (nm) 491 | Emission (nm) 516 | Quantum yield 0.92 |
Example protocol
AT A GLANCE
Chemical Properties of Casein
Appearance: Light yellow powder
Excitation/Emission: 494/521 nm
Solvent: Water
PREPARATION OF STOCK SOLUTION
Casein, FITC-conjugated stock solution:
Make a 5 - 10 mg/mL Casein, FITC-conjugated stock solution in PBS buffer.
PREPARATION OF WORKING SOLUTION
Casein FITC-conjugated working solution (2X):
Dilute the FITC-conjugated stock solution into 50 - 100 mM Tris buffer (pH 7.4) at 100 - 400 μg/mL. The 2X Assay working solution is designed for detecting the activity of chymotrypsin, trypsin, thermolysin, proteinase K, protease XIV, and human leukocyte elastase. For other proteases, please refer to Table 1 for the appropriate assay buffer formula. The optimum concentration of the assay working solution should be determined experimentally for individual proteases.
SAMPLE EXPERIMENTAL PROTOCOL
- Mix equal volume of the trypsin standards or samples with 2X Assay working solution.
- Monitor the fluorescence increase at Ex/Em = 490/525 nm.
a. For kinetic reading: Immediately start measuring fluorescence intensity continuously and record data every 5 minutes for 30 minutes.
b. For end-point reading: Incubate the reaction at a desired temperature for 30 to 60 minutes, protected from light. Then measure the fluorescence intensity.
Table 1. Appropriate assay buffer formula for Assay working solution.
Protease | 1X Assay Buffer |
Cathepsin D | 20 mM Sodium Citrate, pH 3.0 |
Papain | 20 mM sodium acetate, 20 mM cysteine, 2 mM EDTA, pH 6.5 |
PAE | 20 mM sodium phosphate, pH 8.0 |
Pepsin | 10 mM HCl, pH 2.0 |
Porcine pancreas elastase | 10 mM Tris-HCl, pH 8.8 |
Subtilisin | 20 mM potassium phosphate buffer, pH 7.6, 150 mM NaCl |
Spectrum

Spectral properties
Correction Factor (280 nm) | 0.35 |
Extinction coefficient (cm -1 M -1) | 73000 |
Excitation (nm) | 491 |
Emission (nm) | 516 |
Quantum yield | 0.92 |
Product Family
Name | Excitation (nm) | Emission (nm) | Extinction coefficient (cm -1 M -1) | Correction Factor (260 nm) | Correction Factor (280 nm) |
Casein, TAMRA-conjugated | 552 | 578 | 90000 | 0.32 | 0.178 |
Images
Citations
Authors: Tatsumi, Kazuya and Hsu, Chi Hsuan and Suzuki, Atsushi and Nakabe, Kazuyoshi
Journal: Heat and Mass Transfer (2018): 2607--2616
Authors: Tatsumi, Kazuya and Hsu, Chi Hsuan and Suzuki, Atsushi and Nakabe, Kazuyoshi
Journal: Heat and Mass Transfer (2017): 1--10
Authors: Tatsumi, K and Hsu, CH and Suzuki, A and Nakabe, K
Journal: (2016): 032097
Authors: Tatsumi, Kazuya and Tozaki, Akihisa and Nakabe, Kazuyoshi
Journal: (2011): T10167--T10167
References
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Journal: J Dairy Sci (2005): 3392
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Journal: J Alzheimers Dis (2005): 37
Authors: Cilenti L, Lee Y, Hess S, Srinivasula S, Park KM, Junqueira D, Davis H, Bonventre JV, Alnemri ES, Zervos AS.
Journal: J Biol Chem (2003): 11489
Authors: Lee EH, Kim CS, Cho JB, Ahn KJ, Kim KH.
Journal: Dis Aquat Organ (2003): 85
Authors: Rudyak SG, Brenowitz M, Shrader TE.
Journal: Biochemistry (2001): 9317
Authors: Scott ME, Dossani ZY, S and kvist M., undefined
Journal: Proc Natl Acad Sci U S A (2001): 13978
Authors: Fajardo-Lira C, Oria M, Hayes KD, Nielsen SS.
Journal: J Dairy Sci (2000): 2190
Authors: Savopoulos JW, Carter PS, Turconi S, Pettman GR, Karran EH, Gray CW, Ward RV, Jenkins O, Creasy CL.
Journal: Protein Expr Purif (2000): 227
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