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Cat. No.: RSA-5 (for 5mg)

Cat. No.: RSA-20 (for 20mg)

Cat. No.: RSA-100 (for 100mg)

Description

Streptavidin is a tetrameric protein composed of identical subunits. Each subunit binds one biotin molecule with a KD of ~1×10^-15M. The preparation contains an N- and C-terminal shortened variant (core streptavidin) with improved properties concerning homogeneity, solubility, resistance towards proteolytic degradation, and accessibility of the biotin binding pocket compared to native streptavidin.

The molecular mass for the native protein is ~52kDa per tetramer, but under extreme denaturing conditions, giving a major band at about ~13kDa. Streptavidin has four binding sites for biotin, as does avidin. Both have been used extensively as probes in immunochemical systems, conjugated to antibodies, enzymes, or fluorochromes. However, avidin is highly basic (pI 10.5), compared to streptavidin (pI 5-6). Avidin has a slightly higher binding capacity for biotin than streptavidin does, but it has glycosylated side chains which give higher backgrounds in blotting techniques than does streptavidin, which is not a glycoprotein. Streptavidin is more resistant than avidin to dissociation into subunits by guanidinium chloride.

Purity

>98% by SDS-PAGE and HPLC analyses

Biological Activity

>17U/mg (one unit binds 1μg D－biotin)

A282

3.1 (0.1% solution)

Physical Appearance

Sterile colorless liquid

Formulation

A 0.2μm filtered concentrated sterile solution in ultrapure water.

Endotoxin

Less than 0.1EU/μg of rStreptavidin as determined by LAL method.

Only for research and not intended for treatment of humans or animals

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