Porphyrins

{
  "id": "MLC-T-ENV-021636",
  "term": "Porphyrins",
  "field": "Environment",
  "definition": "1. A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.\n\n2. Any of various compounds with a structure that consists essentially of four pyrrole rings joined by four =CH- groups ; especially : one (as chlorophyll or hemoglobin) containing a central metal atom and usually having biological activity.",
  "references": [
    "NIH Genetics Home Reference Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/porphyrins/"
}