FORMATION OF WATER-SOLUBLE PORPHYRINS AND PROTOPORPHYRIN-IX IN 5-AMINOLEVULINIC-ACID-INCUBATED CARCINOMA-CELLS

The bioconversion of 5-aminolevulinic acid (ALA) into hydrophobic prot oporphyrin IX and other water-soluble porphyrins was investigated in E hrlich ascite carcinoma (EAC) cells and in a myeloma cell line. The ef fects of irradiation (514 nm), temperature, incubation time and added glucose on the relative porphyrin concentrations (protoporphyrin vs. w ater-soluble porphyrins) were examined. Variations in these parameters induced a change in the amount of water-soluble porphyrins relative t o protoporphyrin IX. The main component of the hydrophilic porphyrins was found to be uroporphyrin (Up), with minor components of coproporph yrin (Cp) and other carboxyporphyrins. The enhanced production of wate r-soluble porphyrins appears to be associated with alterations in the activities of the various enzymes in the heme biosynthetic pathway, re sulting, for example, in the reduction in the activity of mitochondria l enzymes.