Protein labeling and modification is a powerful tool for
the isolation and analysis of proteins. The ProtOn™ Protein
Labeling Kits simplify the attachment of either biotin or
fluorescein to antibodies or other proteins. Vector Laboratories
offers a variety of reagents and kits for protein labeling
allowing for greater flexibility of experimental design.
Two functional groups on proteins that are often used in protein
modification are primary amino groups, present in lysine residues
and chain termini, and thiol groups in cysteine residues. The
objective for protein modification determines the functional group
that is chosen for labeling. Generally, a protein will have many
primary amino groups accessible on its surface. Modification
of these surface primary amino groups usually does not affect
binding or enzymatic activity of the protein. This allows several
labels to be covalently attached and subsequently detected and
visualized. Thiol groups are usually less abundant and may be
involved in structual elements of the protein like disulfide bridges.
Modification of thiol groups, on the other hand, may yield insight
into protein structure and function.
Vector Laboratories offers reagents for the attachment of labels
to either primary amino groups or thiol groups along with their
corresponding detection reagents.
Glycoproteins may also be labeled with biotin hydrazide through
their carbohydrate groups.
ProtOn™ Protein Labeling Kits
The ProtOn™ protein labeling kits are designed for the simple and fast labeling of proteins with biotin or fluorescein. The kits are ideally suited to label antibodies, hormones, or other proteins as well as other macromolecules containing primary amino groups. Labeled proteins can be used in a number of applications, such as immunological assays, fluorescence microscopy, investigation of protein-protein interactions, etc.
The ProtOn™ labeling reagents react with primary amines
(i.e. lysine residues or terminal amino groups) on the protein
forming a stable covalent bond.
Each kit contains all the components needed for at least five
labeling reactions (up to 1 mg of protein per reaction). Kit components include:
Gel Filtration Slurry
5 x 1 ml Spin Columns
5 x 2 ml Collection Tubes
Agarose Avidin D Slurry**
*N-hydroxysuccinimidyl-6-(biotin amido) hexanoate or fluorescein isothiocyanate.
**Included in biotin labeling kit only (for measuring degree of biotinylation).
Paraffin embedded human prostate tissue stained using rabbit anti-PSA labeled with the ProtOn™ Biotin Labeling Kit and detected with VECTASTAIN® Elite® ABC Reagent and Vector® DAB substrate.
Paraffin embedded human prostate tissue stained directly with rabbit anti-PSA labeled with the ProtOn™ Fluorescein Labeling Kit and mounted in VECTASHIELD® HardSet™ and PI.