@article{mbs:/content/journal/micro/10.1099/00221287-15-2-404, author = "Lascelles, June", title = "An Assay of Iron Protoporphyrin based on the Reduction of Nitrate by a variant Strain of Staphylococcus aureus; Synthesis of Iron Protoporphyrin by Suspensions of Rhodopseudomonas spheroides", journal= "Microbiology", year = "1956", volume = "15", number = "2", pages = "404-416", doi = "https://doi.org/10.1099/00221287-15-2-404", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-15-2-404", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "SUMMARY: A growth requirement for haematin by a streptomycin-resistant strain of Staphylococcus aureus was abolished by adding pyruvate or acetate. Growth in the absence of haematin was improved by addition of purines and uracil. Under anaerobic conditions growth occurred in the presence of nitrate when haematin was added. Suspensions of organisms grown in the absence of haematin reduced nitrate to nitrite when incubated in buffered glucose with haematin, and the amount of nitrite formed was proportional to the concentration of haematin over a range from 0·03 to 0·25 μm-mole/ml. This method was used to assay iron protoporphyrin formed by suspensions of Rhodopseudomonas spheroides. This organism synthesizes iron protoporphyrin as well as free porphyrins when incubated anaerobically in the light with δ-aminolaevulic acid, iron salts and an oxidizable substrate; cobalt ions inhibit the formation of iron protoporphyrin.", }