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Cathepsin D Activity Fluorometric Assay Kit

based on 3 citations in multiple journalsCathepsin D Activity Fluorometric Assay Kit34.1 4
Catalog #: K143

Product Details

Cat # +Size K143-100
Size 100 assays
Detection Method Fluorescence (Ex/Em 328/460)
Species Reactivity Mammalian
Applications Detects alternative proteolytic enzymes such as the lysosomal cathepsin proteases that can initiate or propagate proapoptotic signals.
Features & Benefits • Simple one-step procedure; takes only 1-2 hours
• Fast and convenient
• Cathepsin-D assay is straightforward, and can be adapted to 96-well plate assays.
Kit Components • CD Cell Lysis Buffer
• CD Reaction Buffer
• CD Substrate (1mM)
Storage Conditions -20°C
Shipping Conditions Gel Pack
USAGE For Research Use Only! Not For Use in Humans.


Apoptosis can be mediated by mechanisms other than the traditional caspase-mediated cleavage cascade. There is growing recognition that alternative proteolytic enzymes such as the lysosomal cathepsin proteases may initiate or propagate proapoptotic signals. Cathepsins are lysosomal enzymes that are also used as sensitive markers in various toxicological investigations. The Cathepsin-D Activity Assay kit is a fluorescence-based assay that utilizes the preferred cathepsin-D substrate sequence GKPILFFRLK(Dnp)-D-R-NH2) labeled with MCA. Cell lysates or other samples that contain cathepsin-D will cleave the synthetic substrate to release fluorescence, which can then easily be quantified using a fluorometer or fluorescence plate reader at Ex/Em = 328/460 nm.

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What is the preferential cleavage site for the substrate in the Cathepsin D activity kit?
For the substrate that we use GKPILFFRLK(Dnp)-DR-NH2) labeled with MCA. Cleavage occurs at the Phe-Phe amide bond resulting in enhanced fluorescence.
How should tissue lysates be prepared?
Samples should be completely homogenized in the assay buffer, preferably using a Dounce homogenizer. Substances such as EDTA (> 0.5mM), ascorbic acid (> 0.2%), sodium azide (> 0.2%), NP-40 and Tween-20 (>1%) are known to interfere with these assays and should be avoided in sample preparation.
Will this kit work with mouse or rat samples?
This kit is compatible with all mammalian samples including mouse and rat.
Can we interchange the buffer from this kit with K143?
Each buffer is of different composition and they cannot be used
Can the kit work on bacteria or yeast cells?
The kit has been standardized for mammalian cells only
What is the exact volume of sample required for this assay?
There is no specific volume we can recommend for the amount any sample to be used since it is completely sample concentration and quality based. You have to do a pilot expt with multiple sample volumes to determine the optimal volume which gives a reading within the linear range of the standard curve. Please refer to the citations for this product to see what other clients have used with similar sample types.
Do you have trial sizes of this kit?
Unfortunately, we do not have trial sizes of this kit available. However, if you are based in the US or Canada, we will give you a 10% off list price introductory discount on its purchase price. If you are based out of this area please contact yopur regional BioVision distributor.
What is the shelf life of this kit?
The expiry date is typically 1 year from the date of shipment
Can we purchase individual components of this kit?
Yes, you can purchase any of the kit's components without the whole kit. Please refer to the component Cat #s mentioned on the datasheet for ordering.
Can we use an alternate buffer for sample preparation (cell lysis, sample dilutions etc)?
Our assay buffers are optimized for the reactions they are designed for. They not only contain some detergents for efficient lysis of your cells/tissue, but also contain some proprietary components required for the further reactions. Therefore, we highly recommend using the buffers provided in the kit for the best results.
Are Cathepsin D substrates used in K143 and K148 the same or different? Can I use K148 substrate in K143?
The substrates in K143 and K148 are the same. Therefore, the you can use K148 substrate in K143.
Sumit Siddharth, Concomitant Inhibition of Cytoprotective Autophagy Augments the Efficacy of Withaferin A in Hepatocellular Carcinoma. Cancers (Basel)., March 2019;  30934990.
Park et al., Development of pheochromocytoma in ceramide synthase 2 null mice. Endocr. Relat. Cancer, Aug 2015; 22: 623 - 632.
Liu et al., Urinary proteins induce lysosomal membrane permeabilization and lysosomal dysfunction in renal tubular epithelial cells. Am J Physiol Renal Physiol, Mar 2015; 308: F639 - F649.
Vitner, E. et al. Altered Expression and Distribution of Cathepsins in Neuronopathic Forms of Gaucher Disease and in Other Sphingolipidoses. Hum. Mol. Genet. 2010; 10.1093/hmg/ddq273.
For more citations of this product click here