ALAS is an alias for the gene, 5'-aminolevulinate synthase 1, in humans. Other names include: 5-aminolevulinate synthase, nonspecific, mitochondrial-H; 5-aminolevulinic acid synthase 1; Delta-ALA synthase 1; Delta-aminolevulinate synthase 13H; MIG4. The encoded protein is an enzyme with an amino acid length of 640 and a mass of 70.6 kDa. Other isoforms may exist. ALAS is a member of the Class-II pyridoxal-phosphate-dependent aminotransferase family. This gene shares homology with other species, including: Fly, Mouse, Rat, E. coli.