Whole IgG antibodies are isolated as intact molecules from antisera by immunoaffinity chromatography. They have an Fc portion and two antigen binding Fab portions joined together by disulfide bonds and therefore they are divalent. The average molecular weight is reported to be about 160 kDa. The whole IgG form of antibodies is suitable for the majority of immunodetection procedures and is the most cost effective.
Alexa Fluor® 594-conjugated antibodies absorb light maximally around 591 nm and fluoresce with a peak around 614 nm. They are brighter, more photostable, and more hydrophilic than Texas Red conjugates. Alexa Fluor® 594 conjugates are brighter than red-fluorescing conjugates, and they provide more color separation from green-fluorescing dyes than DyLight 549, Cy3, and TRITC conjugates. They are the best choice for immunofluorescence detection in the deep-red region of the visible spectrum.