Oxygen is absolutely critical for the survival of mammalian cells. Hypoxia induced factor (HIF) is a transcriptional complex that plays a central role in mammalian oxygen homeostasis. There are 3-types of alpha subunits (HIF1-3alpha) and one HIF-beta subunits. However, the three HIF-alpha subunits are regulated by oxygen in a similar fashion, i.e. by regulated stabilization of the alpha-subunits. Under normal conditions, HIF-alpha Prolines are hydroxylated at Pro-402 and Pro-564. This allows binding of von Hippel-Lindau (VHL), the substrate recognition component of the E3 ubiquinated ligase complex, subsequent ubiquitination and degradation of HIF-alpha by the proteasome. Under hypoxic conditions, hydroxylation of HIF-alpha is inhibited and this prevents HIF-alpha degradation. The enzymes responsible for HIF-hydroxylation are known as HIF-prolyl hydroxylases (PHD1-3 or HPH1, HPH2, and HPH3). The three PHDs have been identified to hydroxylate the motif, LXXLAP* with *P being the hydroxyproline. A novel putative proline hydroxylase, PH-4, with an N-terminal EF-hand motif and a C-terminal catalytic domain with 1 transmembrane domain has been identified in endoplasmic reticulum. PH-4 showed approx. 10-15% homology with the collagen prolyl 4-hydroxylases, PH-alpha I, and PH-alpha II. Human PH-4 (502-aa, chromosome 3pp21.3) is highly expressed in most tissues. Like PHD1-3, PH-4 suppressed the HIF transactivation activity, dependent on the consensus oxygen-dependent degradation domain (ODDD) proline residues. Ph-4 levels correlated with the cellular HIF concentration. Therefore, PH-4 may also be involved in cellular oxygen sensing mechanism. Source: 17aa peptide of Human PH-4/EGLX (1) Location: ~C-terminus Species Sequence Homology: Mouse-94% Applications: Suitable for use in ELISA as a control peptide. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20C. Stable for 12 months at -20C. Reconstitute with sterile buffer or ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
Purity:
Purified
Form:
Supplied as a lyophilized powder from PBS, 0.05% sodium azide.
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