The pH dependency of protoporphyrin IX formation in cells incubated with 5-aminolevulinic acid.
Chinese hamster cells (V79) and human adenocarcinoma cells (WiDr) were incubated with 5-aminolevulinic acid (ALA) at different pH values and the rate of production of protoporphyrin IX (PpIX) was measured. The rate of production increased with pH in the range 6.0-7.5. Above pH 7.5 the rate decreased, possibly due to a reduced metabolic activity of the cells. The observations may be explained by the known pH-dependency of the activity of porphobilinogen deaminase (PBGD) and are in agreement with the assumption that PBGD constitutes a rate-limiting step in the synthesis of PpIX from ALA.
Bech
O
O
Institute for Cancer Research, Oslo, Norway.
Berg
K
K
Moan
J
J
D000230:Adenocarcinoma / Q000378:metabolism; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D003110:Colonic Neoplasms / Q000378:metabolism; D006224:Cricetinae; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011524:Protoporphyrins / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D011506:Proteins; D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX