Porphobilinogen deaminase in human erythrocytes: purification of two forms with apparent molecular weights of 40 kDa and 42 kDa

Abstract

Porphobilinogen deaminase was purified from human erythrocytes by ion-exchange chromatography, gel filtration and hydrophobic interaction chromatography. Two forms of the enzyme were isolated, with apparent molecular weights of 40 kDa and 42 kDa, and in relative amounts of 85% and 15%, respectively. Both forms were found to have an N-terminal amino acid sequence identical to that published for the erythropoietic form of porphobilinogen deaminase, as deduced from a cDNA clone. The two forms present could each be separated into three differently charged subforms by Mono Q chromatography.

Key Words:

• acute intermittent porphyria
• enzyme purification
• hydroxymethyl-bilane synthase