NorthernLights™ Fluorescent Secondary Antibodies & Streptavidin Conjugates

NorthernLights™ fluorescent secondary antibodies and streptavidin conjugates are bright and resistant to photobleaching. We are currently offering secondary antibodies recognizing mouse, rat, goat, sheep, and rabbit IgG as well as chicken IgY. These reagents are available with three distinct excitation and emission maxima, making them ideal for multi-color fluorescence microscopy (Figure 1). Their spectral properties are similar to several frequently used fluorochromes and can be used with common filter sets and/or lasers (see the table below).

NorthernLights™ Highlights

• Bright
• Photostable: Resistant to photobleaching
• Comparable spectral properties to many common fluorochromes limiting the need for additional instrumentation
• Specific antibodies deliver low background and high signal-to-noise ratio
• Stable in alcohols and xylene
• Suitable for fluorescence microscopy and flow cytometry

Streptavidin-conjugates

Streptavidin, a protein of 55,000 Daltons, can bind 4 moles of biotin per mole of protein. The complex formed between streptavidin-biotin is stable over a wide range of pH and temperatures. Streptavidin lacks carbohydrate residues present in the avidin molecule reducing non-specific interactions with surface molecules. The dissociation constant for biotin is approximately 10-15 M. Streptavidin conjugated NorthernLights Fluorochromes are an excellent choice for visualization of proteins detected using biotinylated antibodies.

NorthernLights Secondary Reagents	Cat. #	Abs/Em Maxima	Laser (Ex)	Fluorochromes with Comparable Spectrums (Abs/Em)
NL-493 anti-Sheep IgG	NL012	493/514	Argon (488)	FITC (492/520) Cy™2 (489/506) Alexa Fluor® 488 (494/519)
NL-493 anti-Rabbit IgG	NL006
NL-493 anti-Mouse IgG	NL009
NL-493 anti-Rat IgG	NL015
NL-493 anti-Goat IgG	NL003
NL-493 Streptavidin	NL997
NL-493 anti-Chicken IgY	NL018
NL-557 anti-Sheep IgG	NL010	557/574	Krypton (568) HeNe (543)	Phycoerythrin (565/575) Rhodamine Red™ X (570/590) Cy™3 (548/562)
NL-557 anti-Rabbit IgG	NL004
NL-557 anti-Mouse IgG	NL007
NL-557 anti-Rat IgG	NL013
NL-557 anti-Goat IgG	NL001
NL-557 Streptavidin	NL999
NL-557 anti-Chicken IgY	NL016
NL-637 anti-Sheep IgG	NL011	637/658	HeNe (633)	Allophycocyanin (645-660) Alexa Fluor® 647 (650-668) Cy™5 (650/670)
NL-637 anti-Rabbit IgG	NL005
NL-637 anti-Mouse IgG	NL008
NL-637 anti-Rat IgG	NL014
NL-637 anti-Goat IgG	NL002
NL-637 Streptavidin	NL998
NL-637 anti-Chicken IgY	NL017

Click for larger image

Figure 1. Rat cortical stem cell differentiation was monitored using multi-color immunocytochemistry. Neural progenitors were labeled with a Goat Anti-Rat Nestin Antigen Affinity-purified Polyclonal Antibody (R&D Systems, Catalog # AF2736) and stained with a NorthernLights-493-conjugated Donkey Anti-Goat Secondary Antibody (R&D Systems, Catalog # NL003; green). Differentiated neurons were labeled with a Mouse Neuron-specific Anti-beta-III Tubulin Monoclonal Antibody (TuJ-1; R&D Systems, Catalog # MAB1195) and stained using a NorthernLights-557-conjugated Donkey Anti-Mouse Secondary Antibody (R&D Systems, Catalog # NL007; red). Nuclei were stained with DAPI (blue).