IRDye® 800RS Casein Protease Substrate is a general substrate used to detect protease activity. Casein a protein found in milk, is over-labeled with IRDye 800RS producing a quenched substrate for use in protease assays. This near-infrared protease substrate has significant advantages compared to protease assays using visible fluorescence.

Advantages:

• Simple - Incubate sample or known protease with labeled substrate, measure fluorescence, quantify protease concentration from standard curve.
• Enhanced assay sensitivity due to low infrared background fluorescence
• Requires a fraction of the substrate compared to visible
  fluorescence kits
• Improved detection limits of protease activity
• Up to 20-fold fluorescence intensity enhancement upon digestion
• Can be used for protease inhibitor screening
• Versatile - No stop solution to add and fluorescence is detected at the end of incubation. System allows for monitoring reactions over time.

Assay Description

When the IRDye 800RS Casein Substrate is over-labeled with IRDye 800RS, the IRDye 800RS fluorophores are quenched due to intramolecular interactions of dye molecules in close proximity to each other.

	Figure 1. Schematic of IRDye 800RS Casein Protease Substrate. Fluorescence increases upon protease substrate digestion.
	Figure 2. A, B, and C are three replicates. Column 1: buffer only; column 2: trypsin only; and column 3: the substrate only, IRDye 800RS Casein. A two-fold dilution series of trypsin from 5 µg/mL to 19.7 ng/mL is shown in columns 4-12 respectively, at a substrate concentration of 20 nM.

Ordering Information: