Proteins oxygen level

Keitzmann, T., H. Schmidt, K. Unthan-Feschner, I. Probst, and K. Jungermann (1993). A ferro-heme protein senses oxygen levels which modulate the glucagon dependent activation of the PEPCK gene in rat hepatocyte cultures. Biochem. Biophys. Res. Comm. 195 792-798. 

Two scientists working in Baltimore discovered what they called the master protein, HIF , which controlled the growth of new blood and oxygen levels in the red blood cells, so essential for curing tumours, cancers and helping recovery after heart attacks.2... 

Three isoforms of HIF-a [HIF-la, HIF-2a (endothelial PAS domain protein), and HIF-3a] have been defined in humans and are encoded by distinct loci (19, 20). HIF-la and HIF-2a are more important than HIF-3a in the hypoxic response. Three isoforms of HIF-P [HIF-lp (ARNT), ARNT2 (21), and ARNT3 (22)] exist HIF-ip (ARNT) is the most common form. Each HIF-a isoform can interact with any HIF-3 subunit (23). mRNA levels of HIF-la, HIF-2a, and HIF-ip are reportedly not affected by oxygen levels (7, 24, 25), but levels of HIF 3a mRNA increased after two hours of hypoxia (26, 27). 

Ubiquitylation is required for the degradation of hypoxia inducible factor (HIF) on hydroxylation at high oxygen levels (120). Maintaining the circadian clock requires the ubiquitylation and degradation of proteins that inhibit the CLOCK (a protein named from circadian locomotor output cycles kaput gene) transcription factor (121). 

PERI). The members of this protein family tend to act as environmental sensors. For instance, while the AhR mediates responses to xenobiotics, HIFl-Alpha mediates responses to low oxygen levels, and PERI and MOP3 are involved in the circadian rhythmicity, which, in part, is a response to light. 

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