Fluidic Analytics Ltd, a pioneer in protein analysis and the company behind in-solution diffusional sizing, has launched a time-saving and affordable protein labeling kit—fluidiphore rapid amine 503. Absorbing at 503 nm, the new kit can be used with a multitude of techniques including the company’s groundbreaking Fluidity One-W instrument for protein interaction analysis.
Fluorescent labeling of proteins such as antibodies, DNA and lipids is widely used to investigate and better understand protein structure and function. There are various fluorescent dyes available on the market, most of which require a long labeling process over several hours and a purification step to remove excess dye.
Fluidic Analytics’ fluidiphore labeling kit is extremely rapid, taking just 30 minutes to bind proteins rather than four hours to overnight, as is required by other kits. In addition, the fluidiphore kit uniquely does not require a purification step. This is due to a clever ‘triple-lock’ against background effects. Firstly, the absorbance of the dye shifts from 612 nm (free) to 503 nm when conjugated, meaning that unbound dye will not fluoresce at the same excitation wavelength. Quantum yield (the ratio of fluorescence emission to absorption) also increases upon conjugation meaning that unbound dye will have a much weaker signal than bound. Thirdly, any unused dye hydrolyses during the labeling process becoming inactive and unable to bind, therefore preventing the shift in absorbance and increase in quantum yield.
In addition, there is also a useful observable color change from blue to red/yellow which confirms that labeling is taking place, giving researchers additional confidence in the process.
Dr Alison Ilsley, Applications Scientist at Fluidic Analytics undertook an objective review of five different types of labeling kits available on the market, including fluidiphore rapid amine 503. She commented, “It takes approximately five minutes to add the label to the protein and just 30 minutes for labeling to take place. This makes the process much quicker compared to other kits on the market. The fact that there is no purification step is invaluable for researchers who spend a lot of time labeling proteins.”
The fluidiphore rapid amine 503 labeling kit is ideal for use with Fluidic Analytics’ Fluidity One-W instrument to study proteins such as membrane proteins, multi-protein complexes, and intrinsically disordered proteins. The Fluidity One-W enables researchers to accurately assess on-target protein interactions in solution, even in complex, unpurified backgrounds such as crude lysates or blood plasma. The instrument reports absolute size of bound and unbound species, stoichiometry and the nature of binding can be assessed at the same time as binding affinity—giving a complete picture of binding events.