This revealed a heterodimeric complex, comprising a 120 kDa HIF-1α subunit and a 91–94 kDa HIF-1β subunit (also known as aryl hydrocarbon receptor nuclear translocator, ARNT).28 Later in the same year, the protein domains of HIF-1α and HIF-1β were also determined.29 In 1996, Semenza et al. made another significant discovery by demonstrating that HIF-1α is capable of inducing VEGF, which plays a crucial role in angiogenesis.30 Coronary artery disease can lead to myocardial ischemia, resulting in inadequate perfusion and localized hypoxia. Here, ARNT is linked to coronary artery disorder.