CISD1 Protein, Human (His)

The CISD1 protein acts as an L-cysteine aminotransferase, mediating the reversible transfer between L-cysteine and 2-oxoglutarate. Facilitated by the pyridoxal 5'-phosphate (PLP) cofactor, this process produces 2-oxo-3-sulfanylpropionate and L-glutamic acid. CISD1 Protein, Human (His) is the recombinant human-derived CISD1 protein, expressed by E. coli , with N-His, N-6*His labeled tag.

The CISD1 protein functions as an L-cysteine transaminase, facilitating the reversible transfer of the amino group from L-cysteine to the alpha-keto acid 2-oxoglutarate. This enzymatic process results in the formation of 2-oxo-3-sulfanylpropanoate and L-glutamate. The catalytic cycle is orchestrated in the presence of the pyridoxal 5'-phosphate (PLP) cofactor, which initiates transamination by forming an internal aldimine with the epsilon-amino group of the active site Lys-55 residue on the enzyme (PLP-enzyme aldimine). This internal aldimine is subsequently displaced by the formation of an external aldimine with the substrate amino group (PLP-L-cysteine aldimine). The external aldimine undergoes deprotonation, leading to the formation of a carbanion intermediate. In the presence of 2-oxoglutarate, this intermediate regenerates PLP, ultimately yielding the final products 2-oxo-3-sulfanylpropanoate and L-glutamate. The active site lysine residue is implicated in controlling proton transfer in the carbanion intermediate, while PLP stabilizes the carbanion structure through electron delocalization, a phenomenon known as the electron sink effect. Additionally, CISD1 plays a crucial role in regulating the maximal capacity for electron transport and oxidative phosphorylation and may be involved in iron-sulfur cluster shuttling and/or redox reactions. Notably, it can transfer the [2Fe-2S] cluster to an apo-acceptor protein, particularly under oxidative stress conditions, suggesting a role as a redox sensor that regulates mitochondrial iron-sulfur cluster assembly and iron trafficking.

Human

E. coli

N-6*His

Q9NZ45/NP_060934.1 (K32-T108)

55847  [NCBI]

KRFYVKDHRNKAMINLHIQKDNPKIVHAFDMEDLGDKAVYCRCWRSKKFPFCDGAHTKHNEETGDNVGPLIIKKKET

Approximately 14 kDa.

• 
  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized from sterile PBS, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years from date of receipt. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.