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Human SIRP alpha/CD172a Protein

Product Info

Recombinant Human SIRP alpha/CD172a Protein is expressed from Expi293 with His tag at the C-terminal. It contains Glu31-Arg370.[Accession | P78324]

Molecular Weight

The protein has a predicted MW of 38.1 kDa. Due to glycosylation, the protein migrates to 45-65 kDa based on Tris-Bis PAGE result.


Less than 1EU per μg by the LAL method.


> 95% as determined by Tris-Bis PAGE
> 95% as determined by HPLC


Lyophilized from 0.22μm filtered solution in PBS (pH 7.4). Normally 5 % trehalose is added as protectant before lyophilization.


Centrifuge tubes before opening. Reconstituting to a concentration more than 100 μg/ml is recommended. Dissolve the lyophilized protein in distilled water.


The product should be stored at -70℃ or -20℃.

Assay Data
Tris-Bis PAGE

Human SIRP alpha on Tris-Bis PAGE under reduced condition. The purity is greater than 95%.


The purity of Human SIRP alpha is greater than 95% as determined by SEC-HPLC.


Immobilized Human SIRP alpha at 0.5μg/ml (100μl/well) on the plate. Dose response curve for Anti-SIRP alpha Ab., hFc Tag with the EC50 of 11.7ng/ml determined by ELISA.


Immobilized Human SIRP alpha at 0.5μg/ml (100μl/Well). Dose response curve for Human CD47, hFc Tag with the EC50 of 27.4ng/ml determined by ELISA.

Blocking Data

Serial dilutions of Anti-SIRP alpha Antibody were added into Human SIRP alpha, His Tag: Biotinylated Human CD47, His Tag binding reactions.The half maximal inhibitory concentration(IC50) is 73.46ng/ml.

SPR Data

Human SIRP alpha, His Tag captured on Protein A Chip via Anti-His Antibody can bind Human CD47, hFc Tag with an affinity constant of 20.6nM as determined in SPR assay (Biacore T200).


Signal regulatory protein α (SIRPα) is a regulatory membrane glycoprotein from SIRP family expressed mainly by myeloid cells and also by stem cells or neurons.SIRPα acts as inhibitory receptor and interacts with a broadly expressed transmembrane protein CD47 also called the "don´t eat me" signal.Cancer cells highly expressed CD47 that activate SIRP α and inhibit macrophage-mediated destruction.


CD172 antigen-like family member A; CD172a antigen; CD172a;BIT; BITbrain-immunoglobulin-like molecule with tyrosine-based activation motifs; Brain Ig-like molecule with tyrosine-based activation motifs; Inhibitory receptor SHPS-1; Macrophage fusion receptor; MFR; MFRtyrosine phosphatase SHP substrate 1; MyD-1 antigen; MYD1; MYD-1; P84; protein tyrosine phosphatase, non-receptor type substrate 1; PTPNS1; SHP substrate 1; SHPS1; SHPS-1; SHPS1CD172A; signal-regulatory protein alpha; Signal-regulatory protein alpha-1; Signal-regulatory protein alpha-2; Signal-regulatory protein alpha-3; SIRP alpha; SIRPA; SIRPalpha; Sirp-alpha-1; SIRPalpha2; Sirp-alpha-2; Sirp-alpha-3; SIRPtyrosine-protein phosphatase non-receptor type substrate 1


(1)Weiskopf K , Ring A M , Ho C C M , et al. Engineered SIRP? Variants as Immunotherapeutic Adjuvants to Anticancer Antibodies[J]. Science, 2013, 341(6141):88-91.

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