THE PORPHYRIN PRODUCED BY DIPHTHERIA BACILLUS

recently described the effect of iron on toxin and porphyrin production by Corynebacterium diphtheriae.'He assumed that the porphyrin produced by this organism was hematoporphyrin but recognized the need for final identification of t'he dipht,herial porphyrin by isolation analysis.We have isolated t,he porphyrin produced by the same strain of organism grown on the same medium.In ether its absorption maxima, as determined by a Hartridge reversion spectroscope, are at 622.5, 574.1, 528.9, and 496.9 (order of intensity IV > I > III > II).In 0.15 N HCl, the maxima were at 590.1 and 546.8 (II > I).The methyl ester of this porphyrin was readily soluble in chloroform and in benzene, and moderately soluble in methyl alcohol and in anhydrous ether.From this last solvent), the ester crystallized in thick truncated (oblate) needles with a melting point of 155-157" and remelted at 181-182".Its spectral absorption curve determined with a Hilger photoelectric spectrophotometer was identical with that of coproporphyrin I (a pure specimen of coproporphyrin III was not available).The methyl ester yielded a copper complex melting at 218" and with absorption maxima in chloroform at 563 and 526 (I > II).Chromatography of the methyl ester in benzene through CaC03 or alumina revealed that the material behaved as an entity except for two small zones at the top of the column.These zones have not yet been identified.These properties, especially the phenomenon of the double melting point,, leave little doubt that the porphyrin produced by Corynebacterium diphtheriae is mainly coproporphyrin III.We have isolated yields as high as 4 mg. of pure coproporphyrin III methyl ester per liter of diphtherial culture filtrate.These filtrates constitut.e,therefore, an important and hitherto unexplored source of coproporphyrin III, and details of a method whereby this material can be obtained as a by-product in the large scale production of purified diphtheria toxoid will be published shortly.