ALAS1

The ALAS1 gene provides instructions for the production of an enzyme called delta-aminolevulinate synthase 1 (ALA-synthase) in all of the body's tissues. ALAS1 is one of two genes that carry the information for the production of this enzyme. The other gene that makes delta-aminolevulinate synthase is ALAS2, which is only turned on in red blood cells (erythrocytes). Delta-aminolevulinate synthase 1 is especially important in the liver, where it is used in the production of heme (the iron-containing part of hemoglobin). Hemoglobin is the oxygen-carrying protein in red blood cells.

Delta-aminolevulinate synthase 1 carries out the first step in the production of heme. Each of the steps in heme production is controlled by a different enzyme, each of which is produced from a single gene. The first step in this process is the synthesis of delta-aminolevulinic acid (ALA). Seven other enzymes will modify delta-aminolevulinic acid before it becomes heme. The activity of delta-aminolevulinate synthase 1 determines how much heme the tissues in the body will produce. Delta-aminolevulinate synthase 1 is also used to make other heme-containing proteins; for example, enzymes that process medications and chemicals, and enzymes that produce energy.