ENHANCERS OF THE NON-PEROXIDATIVE METAL PORPHYRIN CHEMILUMINESCENCE REACTION

Metal porphyrins catalyse luminol chemiluminescence at pH13 without ad ded peroxide. The effects of 22 different surface active compounds on this reaction were studied using six metal porphyrins and one metal po rphyrin conjugate. The most active catalyst was Mn-meso-tetra(4-sulpho natophenyl)porphine. Tween-20 enhanced the activity of this catalyst b est at a Tween-20 to luminol ratio of 74:1. However, lauryl sulphate e nhanced best at an optimum lauryl sulphate to luminol ratio of over 10 00:1 and both detergents enhanced the reaction when present below thei r critical micelle concentrations. Negatively charged aliphatic compou nds such as fatty acids enhanced the reaction but positive-charged ali phatic compounds inhibited it. Small differences in enhancer structure resulted in differing enhancement. For example, linoleic acid enhance d Mn-meso-tetraphenyl porphine more than 10-fold, yet linolenic acid i nhibited this catalyst. Conjugation of a metal porphyrin to antibody d id not influence its enhancement by detergents. The results indicate t hat the enhancement mechanism does not require formation of pure deter gent micelles but that direct association between enhancer and catalys t may be important.