ALAD Blocking Peptide

The ALAD enzyme is composed of 8 identical subunits and catalyzes the condensation of 2 molecules of delta-aminolevulinate to form porphobilinogen (a precursor of heme, cytochromes and other hemoproteins). ALAD catalyzes the second step in the porphyrin and heme biosynthetic pathway; zinc is essential for enzymatic activity. ALAD enzymatic activity is inhibited by lead and a defect in the ALAD structural gene can cause increased sensitivity to lead poisoning and acute hepatic porphyria. [provided by RefSeq, Jul 2008]

ALAD: Catalyzes an early step in the biosynthesis of tetrapyrroles. Binds two molecules of 5-aminolevulinate per subunit, each at a distinct site, and catalyzes their condensation to form porphobilinogen. Defects in ALAD are the cause of acute hepatic porphyria (AHEPP). A form of porphyria. Porphyrias are inherited defects in the biosynthesis of heme, resulting in the accumulation and increased excretion of porphyrins or porphyrin precursors. They are classified as erythropoietic or hepatic, depending on whether the enzyme deficiency occurs in red blood cells or in the liver. AHP is characterized by attacks of gastrointestinal disturbances, abdominal colic, paralysis, and peripheral neuropathy. Most attacks are precipitated by drugs, alcohol, caloric deprivation, infections, or endocrine factors. Belongs to the ALADH family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: EC 4.2.1.24; Cofactor and Vitamin Metabolism - porphyrin and chlorophyll; Lyase

Chromosomal Location of Human Ortholog: 9q33.1

Cellular Component: cytosol; nucleus

Molecular Function: identical protein binding; porphobilinogen synthase activity; zinc ion binding; lead ion binding; catalytic activity

Biological Process: porphyrin metabolic process; protoporphyrinogen IX biosynthetic process; protein homooligomerization; heme biosynthetic process

Disease: Porphyria, Acute Hepatic