Conditions of optimal Protein A performance in applications should be determined by the end user.
Protein A binds to many immunoglobulins with high affinity to human IgG1 and IgG2 as well as mouse IgG2a and IgG2b, and with moderate affinity to human IgM, IgA, and IgE as well as mouse IgG1 and IgG3. Protein A binds to the Fc region through interaction with the heavy chain.
Native Protein A is used in multiple commercial products with a long regulatory history. rSPA - our native recombinant Staphylococcal Protein A is an ideal substitute or replacement to native Protein A. rSPA contains the same amino acid sequence and molecular mass as the native Protein A sourced from S. aureus, but without the security of supply concerns associated with Enterotoxin B. rSPA is manufactured in E.coli and with animal-free materials. The recombinant protein is the most modern ligand and will in many cases demonstrate improved target protein binding. It should be considered the ligand of first choice for all new processes not only for its potential performance improvements but also for supply chain security and overall value proposition.
Recombinant Protein A, expressed in E. coli as opposed to the native protein extracted from Staphylococcus aureus, eliminates safety concerns associated with the BL2 organism. S. aureus produces a severely incapacitating toxin, Staphylococcus Enterotoxin B (SEB), considered to be a biological threat agent by the U.S. government. Choosing recombinant Protein A eliminates any concern with SEB.
IA000019-10-2001: rSPA, native recombinant S. aureus Protein A (animal free)
Appearance (liquid): Clear, pale yellow with no particulates
Bioburden: No growth detected
Endotoxin < 1.0 EU/mg
Protein Concentration (A275): 49.4 mg/ml
12% SDS-PAGE Coomasie Stain: Single major band, 48, 000 Daltons
Purity: 98.9% (HPLC), > 95% (SEC)
hIgG Binding: 100.9%
Conductivity: 0.02 mS/cm
UV Spectrum (400 - 500 nm): 100.0% Transmittance
IgG Binding: Binds 3 IgG Istypes
Binding Capacity: ~ 50 mg/ml hIgH
Animal Free: Yes
Entertoxin B Risk: No
Fermentation Organism: E. coli
Sequence: Natural S. aureus
CaptivA PriMAB protein A affinity resins, which combines a 4% agarose bead with the rSPA ligand, is the major component in Opus pre-packed CaptivA PriMAB protein A columns. rSPA can be detected by our Protein A ELISA kit for detection of natural and recombinant Protein A.