Name :
Recombinant Human AHSP Protein
Biological Activity :
Background :
AHSP, also known as ERAF, is a conserved mammalian erythroid protein which belongs to the AHSP family. It is expressed in blood and bone marrow. AHSP facilitates the production of Hemoglobin A by stabilizing free α-globin. It rapidly binds to ferrous α with association (k'(AHSP)) and dissociation (k(AHSP)) rate constants of ≈1 μm(-1) s(-1) and .2 s(-1), respectively, at pH 7.4 at 22 ℃. A small slow phase was observed when AHSP binds to excess ferrous αCO. This slow phase appears to be due to cis to trans prolyl isomerization of the Asp(29)-Pro(3) peptide bond in wild-type AHSP because it was absent when αCO was mixed with P3A and P3W AHSP, which are fixed in the trans conformation. This slow phase was also absent when met(Fe(3+))-α reacted with wild-type AHSP, suggesting that met-α is capable of rapidly binding to either Pro(3) conformer. Both wild-type and Pro(3)-substituted AHSPs drive the formation of a met-α hemichrome conformation following binding to either met- or oxy(Fe(2+))-α. The dissociation rate of the met-α·AHSP complex (k(AHSP) ≈ .2 s(-1)) is ～1-fold slower than that for ferrous α·AHSP complexes, resulting in a much higher affinity of AHSP for met-α. Thus, in vivo, AHSP acts as a molecular chaperone by rapidly binding and stabilizing met-α hemichrome folding intermediates. The low rate of met-α dissociation also allows AHSP to have a quality control function by kinetically trapping ferric α and preventing its incorporation into less stable mixed valence Hemoglobin A tetramers. Reduction of AHSP-bound met-α allows more rapid release to β subunits to form stable fully, reduced hemoglobin dimers and tetramers.
Biological Activity :
Testing in progress
Expression Host :
Human
Source :
E. coli
Tag :
Protein Accession No. :
Q9NZD4
NCBI Gene ID :
Synonyms :
Synonyms :
alpha hemoglobin stabilizing protein
Amino Acid Sequence :
Molecular Weight :
The recombinant human ERAF consists of 102 amino acids and predicts a molecular mass of 11.8 KDa. It migrates as an approximately 12 KDa band in SDS-PAGE under reducing conditions.
Purity :
> 90 % as determined by SDS-PAGE
State of Matter :
Product Concentration :
Storage and Stability :
Samples are stable for up to twelve months from date of receipt at -20℃ to -80℃. Store it under sterile conditions at -20℃ to -80℃. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
Endotoxin Level :
Please contact us for more information.
Protein Construction :
A DNA sequence encoding human ERAF (Q9NZD4) (Met1-Ser102) was expressed.
Buffer Solution :
Lyophilized from sterile PBS, pH 7.4.Please contact us for any concerns or special requirements. Normally 5 % – 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hardcopy of datasheet.
Shipping :
In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature.Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise.
Redissolution :
A hardcopy of datasheet with reconstitution instructions is sent along with the products. Please refer to it for detailed information.
Synonyms :
EDRF Protein, Human; ERAF Protein, Human AHSP 背景信息 AHSP, also known as ERAF, is a conserved mammalian erythroid protein which belongs to the AHSP family. It is expressed in blood and bone marrow. AHSP facilitates the production of Hemoglobin A by stabilizing free α-globin. It rapidly binds to ferrous α with association (k'(AHSP)) and dissociation (k(AHSP)) rate constants of ≈1 μm(-1) s(-1) and .2 s(-1), respectively, at pH 7.4 at 22 ℃. A small slow phase was observed when AHSP binds to excess ferrous αCO. This slow phase appears to be due to cis to trans prolyl isomerization of the Asp(29)-Pro(3) peptide bond in wild-type AHSP because it was absent when αCO was mixed with P3A and P3W AHSP, which are fixed in the trans conformation. This slow phase was also absent when met(Fe(3+))-α reacted with wild-type AHSP, suggesting that met-α is capable of rapidly binding to either Pro(3) conformer. Both wild-type and Pro(3)-substituted AHSPs drive the formation of a met-α hemichrome conformation following binding to either met- or oxy(Fe(2+))-α. The dissociation rate of the met-α·AHSP complex (k(AHSP) ≈ .2 s(-1)) is ～1-fold slower than that for ferrous α·AHSP complexes, resulting in a much higher affinity of AHSP for met-α. Thus, in vivo, AHSP acts as a molecular chaperone by rapidly binding and stabilizing met-α hemichrome folding intermediates. The low rate of met-α dissociation also allows AHSP to have a quality control function by kinetically trapping ferric α and preventing its incorporation into less stable mixed valence Hemoglobin A tetramers. Reduction of AHSP-bound met-α allows more rapid release to β subunits to form stable fully, reduced hemoglobin dimers and tetramers.
References & Citations :
Miele G., et al.,(2001), A novel erythroid-specific marker of transmissible spongiform encephalopathies. Nat. Med. 7:361-364.Zhang Q.-H., et al., (2000), Cloning and functional analysis of cDNAs with open reading frames for 300 previously undefined genes expressed in CD34+ hematopoietic stem/progenitor cells.Genome Res. 10:1546-1560.Kihm A.J., et al.,(2002), An abundant erythroid protein that stabilizes free alpha-haemoglobin.Nature 417:758-763.
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