Eukaryotic translation initiation factor 2-alpha kinase 1 is a protein in humans that is encoded by EIF2AK1 gene. Inhibits protein synthesis at the translation initiation level, in response to various stress conditions, including oxidative stress, heme deficiency, osmotic shock and heat shock. Exerts its function through the phosphorylation of EIF2S1 at 'Ser-48' and 'Ser-51', thus preventing its recycling. Binds hemin forming a 1