Recombinant Human Complement Factor I (CFI) Protein (His-GST&Myc)

Name: Recombinant Human Complement Factor I (CFI) Protein (His-GST&Myc)
Brand: Beta LifeScience
SKU: BLC-01049P
Availability: InStock

Greater than 85% as determined by SDS-PAGE.

Collections: Complement components, Cytokines and growth factors, Recombinant proteins

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Product Overview

Description	Recombinant Human Complement Factor I (CFI) Protein (His-GST&Myc) is produced by our E.coli expression system. This is a protein fragment.
Purity	Greater than 85% as determined by SDS-PAGE.
Uniprotkb	P05156
Target Symbol	CFI
Synonyms	(C3B/C4B inactivator)
Species	Homo sapiens (Human)
Expression System	E.coli
Tag	N-10His-GST&C-Myc
Target Protein Sequence	KACDGINDCGDQSDELCCKACQGKGFHCKSGVCIPSQYQCNGEVDCITGEDEVGCAGFASVTQEETEILTADMDAERR
Expression Range	239-316aa
Protein Length	Partial
Mol. Weight	43.4 kDa
Research Area	Immunology
Form	Liquid or Lyophilized powder
Buffer	Liquid form: default storage buffer is Tris/PBS-based buffer, 5%-50% glycerol. Lyophilized powder form: the buffer before lyophilization is Tris/PBS-based buffer, 6% Trehalose, pH 8.0.
Reconstitution	Briefly centrifuged the vial prior to opening to bring the contents to the bottom. Reconstitute protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL. It is recommended to add 5-50% of glycerol (final concentration) and aliquot for long-term storage at -20°C/-80°C. The default final concentration of glycerol is 50%.
Storage	1. Store at -20°C/-80°C upon receipt, aliquoting is necessary for mutiple use. 2. Avoid repeated freeze-thaw cycles. 3. Store working aliquots at 4°C for up to one week. 4. In general, protein in liquid form is stable for up to 6 months at -20°C/-80°C. Protein in lyophilized powder form is stable for up to 12 months at -20°C/-80°C.
Notes	Repeated freezing and thawing is not recommended. Store working aliquots at 4°C for up to one week.

Target Details

Target Function	Trypsin-like serine protease that plays an essential role in regulating the immune response by controlling all complement pathways. Inhibits these pathways by cleaving three peptide bonds in the alpha-chain of C3b and two bonds in the alpha-chain of C4b thereby inactivating these proteins. Essential cofactors for these reactions include factor H and C4BP in the fluid phase and membrane cofactor protein/CD46 and CR1 on cell surfaces. The presence of these cofactors on healthy cells allows degradation of deposited C3b by CFI in order to prevent undesired complement activation, while in apoptotic cells or microbes, the absence of such cofactors leads to C3b-mediated complement activation and subsequent opsonization.
Subcellular Location	Secreted, extracellular space. Secreted.
Protein Families	Peptidase S1 family
Database References	HGNC: 5394 OMIM: 217030 KEGG: hsa:3426 STRING: 9606.ENSP00000378130 UniGene: Hs.312485
Associated Diseases	Hemolytic uremic syndrome atypical 3 (AHUS3); Complement factor I deficiency (CFI deficiency); Macular degeneration, age-related, 13 (ARMD13)
Tissue Specificity	Expressed in the liver by hepatocytes. Also present in other cells such as monocytes, fibroblasts or keratinocytes.

Gene Functions References

This study has revealed a significant genetic role for CFI-rs13104777 in acute anterior uveitis. This influence may be dependent on human leukocyte antigen (HLA)-B27 and disease laterality. PMID: 27380463
An extremely rare, heterozygous mutation in the gene encoding CFI likely affecting splicing was associated for the first time with atypical hemolytic uremic syndrome. PMID: 28455885
this study illustrates the importance of early versus late diagnosis of CFI deficiency PMID: 28942469
This finding although rare does suggest that screening for chromosomal rearrangements affecting CFI should be undertaken in all aHUS patients particularly if the factor I level is unexplainably low. PMID: 27268256
Factor I binds C3b-Factor H between Factor H domains 2 and 3 and a reoriented C3b C-terminal domain and docks onto the first scissile bond, while stabilizing its catalytic domain for proteolytic activity. PMID: 28671664
Taken together, our data argue that multiple rare and ultra-rare alleles in CFI contribute to AMD pathogenesis; they improve the precision of the assessment of the contribution of CFI to AMD PMID: 28282489
Case Report: thrombotic microangiopathy with mutations in complement factor I and thrombomodulin. PMID: 26613809
Our results indicate that CFI polymorphisms are not significantly associated with VKH syndrome. PMID: 26900322
Patients with advanced atrophic AMD carried these rare variants more frequently than patients with neovascular AMD (11 of 93 [11.8%] vs 40 of 835 [4.8%]; P = .04). PMID: 26767664
Low FI levels are strongly associated with rare CFI variants and age-related macular degeneration. PMID: 25788521
A missense variant (p.V412M) in CFI was discovered in two Tunisian Jewish families with early-onset age-related macular degeneration. PMID: 25986072
Regulatory components of the alternative complement pathway in endothelial cell cytoplasm, factor H and factor I, are not packaged in Weibel-Palade bodies. PMID: 25803806
In this study, the odds of AMD were highest in those with deficient vitamin D status and 2 risk alleles for the CFH and CFI genotypes, suggesting a synergistic effect between vitamin D status and complement cascade protein function. PMID: 26312598
iC3b level, a proteolytically inactive form of C3b, was lower in HCV infected patient sera, reflecting impairment of both C3 convertase and Factor I activity. PMID: 24983375
association between rs10033900 and age-related macular degeneration risk in Han Chinese population PMID: 24642830
The mutations in the regulators CFH, CFI and MCP involve loss-of-function, whereas those for C3 involve gain-of-function. PMID: 25188723
The CFI p.Gly119Arg mutation was identified in 7/521 age-related macular degeneration cases compared to 1/627 age-matched controls; this mutation confers a high risk of disease. PMID: 25352734
CFI genetic variants played an important role in the development of NSCLC in Chinese population. PMID: 25394898
High expression of complement factor I is associated with recurrence in breast cancer. PMID: 25618258
results provide evidence for the role of CFI in the progression of cSCC and identify it as a potential therapeutic target in this nonmelanoma skin cancer PMID: 25184960
This study has revealed a significant association between acute anterior uveitis (AAU) and CFI-rs7356506, suggesting that CFI is involved in the pathogenesis of AAU PMID: 25075123
Neither of the two SNPs most studied (rs10033900 or rs2285714) in the CFI gene was a risk factor for developing neovascular age-related macular degeneration or polypoidal choroidal vasculopathy in a Chinese population. PMID: 24732209
Recurrent aseptic meningo-encephalitis is a rare clinical presentation of complete FI deficiency. PMID: 24142231
An STR polymorphism in intron 7 of human CFI gene on chromosome 4q in 11 Asian populations indicated that Group H alleles in exon 11 of the CFI gene were almost entirely confined to East Asian populations, making it useful in forensic anthropology. PMID: 23688582
We found that 7.8% of advanced age-related macular degeneration cases compared to 2.3% of controls are carriers of rare missense CFI variants. PMID: 24036952
Case Report: patient with atypical haemolytic uremic syndrome with combined membrane cofactor protein CD46 and complement factor I mutations undergoing successful kidney transplantation. PMID: 23519521
Mutations in complement factor I protein is associated with end-stage renal disease in a patient with hemolytic uremic syndrome caused by infections by Escherichia coli strains producing Shiga-like toxins. PMID: 23731345
these findings demonstrate that rare, highly penetrant mutations in CFI contribute to the genetic burden of age-related macular degeneration. PMID: 23685748
rs1136287 in CFI is less likely to be associated in in extremely myopic Japanese individuals. PMID: 23722394
The alternative pathway of complement may play a role in the pathogenesis of HELLP syndrome. PMID: 22594569
Acute hemorrhagic leukoencephalitis (AHLE) is an unreported, rare phenotype for partial complement factor I deficiency. PMID: 22926405
we report four novel mutations and the first large gene deletion in the CFI locus. PMID: 22710145
One SNP (rs10033900) in the CFI gene, which encodes a protein involved in the inflammatory pathway, was significantly associated with myopic choroidal neovascularization in multivariate analysis after correction for multiple testing. PMID: 22678500
Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. PMID: 22514678
factor I were significantly diminished early after trauma. PMID: 22258234
all analyzed cofactors form similar trimolecular complexes with FI and C3b/C4b, and the accessibility of FIMAC and SP domains is crucial for the function of FI PMID: 22393059
Results question whether complement factor I autoantibodies per se predispose to atypical hemolytic uremic syndrome. PMID: 22223611
Forster resonance energy transfer was used to investigate the 10 muM K(D) (210 kD) complex between the N-terminal region of the soluble complement regulator, factor H (FH1-4), and the key activation-specific complement fragment, C3b. PMID: 21936007
Data show that FI is in a proteolytically inactive form, demonstrating that it circulates in a zymogen-like state. PMID: 21768352
Study describes the molecular and functional consequences of two novel mutations of FI. PMID: 21316765
Study identified novel mutations in CFH, CFHR5, CFI, CFB and C3 in American patients with atypical hemolytic uremic syndrome. PMID: 20513133
Role of a common variant near the complement factor I gene in susceptibility to age-related macular degeneration. PMID: 20087399
In a large cohort of 202 patients with aHUS, we identified 23 patients carrying exonic mutations in CFI PMID: 20016463
the FIMAC domain appears to harbor the main binding sites important for the ability of FI to degrade C4b and C3b PMID: 20044478
mutations in complement factor I affect both secretion and function of factor I, which leads to impaired regulation of the complement system in atypical hemolytic uremic syndrome. PMID: 19877009
the last 45 amino acid of the heavy chain, including a disulfide bridge area, did not participate in the serine protease function of factor I PMID: 14967308
Human complement factor I does not require cofactors for cleavage of synthetic substrates. PMID: 15210795
fI and the serine protease domain were found to have similar amidolytic activities but strikingly different proteolytic activities on C3(NH(3)). PMID: 15835912
Mutations in the complement regulators factor H, membrane cofactor protein (MCP), and factor I are associated with atypical hemolytic uremic syndrome. PMID: 16386793
factor I in concert with CR1 on E and factor H in serum due to their cofactor activity are likely to be important contributors PMID: 16920989

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Proteins are sensitive to heat, and freeze-drying can preserve the activity of the majority of proteins. It improves protein stability, extends storage time, and reduces shipping costs. However, freeze-drying can also lead to the loss of the active portion of the protein and cause aggregation and denaturation issues. Nonetheless, these adverse effects can be minimized by incorporating protective agents such as stabilizers, additives, and excipients, and by carefully controlling various lyophilization conditions.

Commonly used protectant include saccharides, polyols, polymers, surfactants, some proteins and amino acids etc. We usually add 8% (mass ratio by volume) of trehalose and mannitol as lyoprotectant. Trehalose can significantly prevent the alter of the protein secondary structure, the extension and aggregation of proteins during freeze-drying process; mannitol is also a universal applied protectant and fillers, which can reduce the aggregation of certain proteins after lyophilization.

Our protein products do not contain carrier protein or other additives (such as bovine serum albumin (BSA), human serum albumin (HSA) and sucrose, etc., and when lyophilized with the solution with the lowest salt content, they often cannot form A white grid structure, but a small amount of protein is deposited in the tube during the freeze-drying process, forming a thin or invisible transparent protein layer.

Reminder: Before opening the tube cap, we recommend that you quickly centrifuge for 20-30 seconds in a small centrifuge, so that the protein attached to the tube cap or the tube wall can be aggregated at the bottom of the tube. Our quality control procedures ensure that each tube contains the correct amount of protein, and although sometimes you can't see the protein powder, the amount of protein in the tube is still very precise.

To learn more about how to properly dissolve the lyophilized recombinant protein, please visit Lyophilization FAQs.