heme

noun

ˈhēm 

: the deep red iron-containing prosthetic group C₃₄H₃₂N₄O₄Fe of hemoglobin and myoglobin

Examples of heme in a Sentence

Recent Examples on the Web

Key Takeaways Lamb and beef are excellent, comparable sources of highly absorbable heme iron. —Lindsay Curtis, Verywell Health, 20 Jan. 2026

These are proteins that contain iron-rich heme groups, which are what enable the transference of electrons step by step from inside the cell to the outside. —Scott Travers, Forbes.com, 11 Jan. 2026

Non-heme iron isn’t as well absorbed as the heme iron found in animal products. —Ruth Jessen Hickman, Health, 16 Dec. 2025

There are a number of reasons why red meat might be a problem, including the high heme iron content, plus the need to cook meat at high temperatures, which can produce carcinogenic compounds. —Bryant Stamford, Louisville Courier Journal, 23 Oct. 2025

Word History

Etymology

International Scientific Vocabulary, from hematin

First Known Use

1925, in the meaning defined above

Kids Definition

heme

noun

ˈhēm 

: a deep red pigment that contains iron and is obtained from hemoglobin

Medical Definition

heme

noun

variants or chiefly British haem

ˈhēm 

: the deep red iron-containing prosthetic group C₃₄H₃₂N₄O₄Fe of hemoglobin and myoglobin that is a ferrous derivative of protoporphyrin and readily oxidizes to hematin or hemin

called also protoheme