cytochrome

American  

[sahy-tuh-krohm] / ˈsaɪ təˌkroʊm /

noun

Biochemistry.

1. any of several carrier molecules in the mitochondria of plant and animal cells, consisting of a protein and an iron-containing porphyrin ring and participating in the stepwise transfer of electrons in oxidation reactions: each cytochrome alternately accepts and releases an electron at a slightly lower energy level in the order designated b, c 1 , c, a, and a 3 .

---

cytochrome British  

/ ˈsaɪtəʊˌkrəʊm /

noun

1. any of a group of naturally occurring compounds, consisting of iron, a protein, and a porphyrin, that are important in cell oxidation-reduction reactions

---

cytochrome Scientific  

/ sī′tə-krōm′ /

1. Any of a class of usually colored proteins that play important roles in oxidative processes and energy transfer during cell metabolism and cellular respiration. Cytochromes are electron carriers. They contain a heme group and are similar in structure to hemoglobin and chlorophyll. The most abundant and stable type is cytochrome c. By comparing different kinds of cytochromes, scientists can trace the evolutionary relationships of the organisms in which they occur.

---

Etymology

Origin of cytochrome

First recorded in 1895–1900; cyto- + -chrome

Example Sentences

Cells with elevated OPA1 develop tightly packed, more numerous folds in their mitochondrial membranes, known as cristae, which trap cytochrome c.

From Science Daily • Nov. 23, 2025

Yu and his team looked to nature for inspiration, in particular to cytochrome P450 enzymes, which are found in most living organisms, and help clear potentially toxic molecules in the human liver.

From Science Daily • Apr. 20, 2024

But for some reason, the nematode version of cytochrome P450 instead turns selectivin into a toxic chemical.

From Science Magazine • May 25, 2023

Once the nematode’s body absorbs it, the worm modifies it with enzymes, called cytochrome P450s, which in many organisms detoxify foreign molecules.

From Science Magazine • May 25, 2023

Figure 4.15 Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain.

From Textbooks • Apr. 25, 2013