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In a recent study, Malik and Lugaci 1 described the research and development of 5-aminolevulinic acid (5-ALA) as a new-generation photosensitizer with high tumor specificity. The use of 5-ALA-based photodynamic technology has since been examined in a number of studies worldwide, such as in photodynamic diagnosis (PDD), in which it is used to detect tumors by illuminating the lesion with a specific wavelength of light to produce fluorescence after administration of 5-ALA; photodynamic therapy (PDT), in which it is used to induce cell death; and in photodynamic screening (PDS), in which porphyrin excretion in the blood and urine is used as a tumor biomarker. Thus, a number of applications using 5-ALA are expected to emerge in the clinical setting. | 5-Aminolevulinic acid (5-ALA) as a photosensitizer5-ALA is a natural amino acid produced in plants and animals, and it is a common precursor of hemoglobin and chlorophyll (Figures 1, 2).Endogenous 5-ALA is generated from glycine and succinyl CoA in the mitochondria by an enzymatic reaction induced by the 5-ALA synthetic enzyme, whereas exogenous 5-ALA may also be introduced into cells by its administration. In normal cells, both endogenous and exogenous 5-ALA produce a precursor through the same biosynthetic and metabolic pathways in the cytoplasm, and the precursor is transported to the mitochondria via the ATP-binding cassette (ABC) subfamily B member 6 (ABCB6) to produce protoporphyrin IX (PpIX). Subsequently, ferrochelatase catalyzes the insertion of ferrous iron into PpIX to form

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An endo ƒÀ-1, 6-glucanase (ƒÀ-1, 6-glucan glucanohydrolase, E. C. 3. 2. 1.) has been purified from the culture filtrate of a strain resembling Rhizopus chinensis in homogeneous form. The procedures involved ammonium sulfate fractionation followed by column chromato graphy of DEAE-cellulose, CM-Sephadex C-50 and BioGel P-60. Various physicochemical and chemical characteristics of the enzyme have been made clear, including complete amino acid composition. Optimum pH, optimum temperature, apparent activation energy for activity, Km and Vmax are 5.5•`6.0, 60•Ž, 4.39 Cal per mole, 9.39•~10-3M glucose equivalents (0.169%) and 43.13 International Units, respectively. The enzyme required no metal ions for its activity, and it hydrolyzed ƒÀ-1, 6-glucan larger than gentiotetraose, forming gentiobiose and gentiotriose as main products. Distribution of ƒÀ-1, 6-glueosidic linkages in polysaccharides is not as aboundant as other ƒÀ-linkages , such as ƒÀ-1, 4 or ƒÀ-1, 3. However, it is well known that the ƒÀ-1, 6-linkage is a component of the cell wall of yeasts and fungi and of the extracellular polysaccharide which is synthesized in growing cultures of Penicillium luteum.1) Recently an enzyme active on ƒÀ-1, 6-•õ Studies on Fungal Enzymes Active in Hydroly sing Yeast Cell Wall.

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