Microscale Protein Labeling Kits conveniently label small amounts (20–100 μg) of purified protein with a bright, photostable Alexa Fluor® dye or the hapten, biotin-XX.

  • Convenient—labeled proteins ready in 2 hours requiring approximately 30 minutes actual hands-on time
  • Versatile—label proteins with molecular weights between 12 and 150 kDa, including IgG antibodies (~150 kDa) and quantities ranging from 20-100 µg
  • Reliable—protein conjugates with stable attachment of fluorescent labels or haptens

Microscale Antibody Labeling Kit Products

Label   Ex/Em† Cat. no.
Emission Color*
Flow Cytometry Imaging  
Alexa Fluor® 488 495/519 A30006              ●           ● Order
Alexa Fluor® 555 555/565 A30007             ● Order
Alexa Fluor® 594 590/617 A30008             ● Order
Alexa Fluor® 647 650/665 A30009              ●           ● Order
Biotin n/a B30010              ●           ● Order
* Gray represents fluorescence emission that is beyond the limit of human vision. † Ex/Em = Fluorescence excitation and emission maxima in nm.  

How Microscale Antibody Labeling Kits Work

The Microscale Protein Labeling Kits use an amine-reactive fluorophore or biotin to covalently attach the label to the protein or IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable; you are using the same chemistry we use to prepare our own primary and secondary conjugates.

Unlike our other antibody labeling kits, these kits have been optimized for labeling proteins between 12 and 150 kDa; thus, they label other proteins besides IgG antibodies.

Any stabilizing proteins (i.e., BSA), must be removed prior to the labeling reaction. Convenient spin columns purify the labeled protein (Figure 1) with yields between 60 and 90%, depending on the molecular weight of the starting material. The entire labeling and purification procedure can be completed in as little as 2 hours—everything needed to perform three conjugations is provided.

APEX Antibody Labeling Kits

Figure 1. Spin filter. (A) An empty filter showing the separate parts. (B) Appearance of the resin bed after centrifugation in a fixed-angle rotor or swinging bucket rotor.

Each Microscale Antibody Labeling Kit includes:
Material Amount
Reactive fluorescent label or hapten 3 vials
Sodium bicarbonate 1 vial
Reaction tubes 3
Spin filters 3
Purification resin 1 vial

Product Information Sheet

Need to Label Other Antibody Amounts?

Zenon® Kits

< 1-20 µg
Microscale Kits

< 1-20 µg
Antibody Labeling kits

< 1-20 µg


Protein Labeling Kits

< 1-20 µg



< 1-20 µg


APEX™ Antibody Labeling kits

10-20 µg

Learn More about APEX™ Antibody Labeling Kits