Practice problem
Substrate (Biology) — Definition & Role
By Valeri Natole
+1 contributors
Contributors
![[1] Molecule that fits into a specific spot on firefly luciferase
[2] Specific spot on firefly luciferase that fits molecule for reaction
[3] Firefly luciferase itself](https://d20khd7ddkh5ls.cloudfront.net/fireflyluciferaserxn.png)
By Ramin Herati [Public domain], via Wikimedia Commons
[1] Molecule that fits into a specific spot on firefly luciferase
[2] Specific spot on firefly luciferase that fits molecule for reaction
[3] Firefly luciferase itself
Fireflies' glow is possible due to firefly luciferase, a protein in firefly cells. Another molecule fits into a specific spot on firefly luciferase, causing a reaction that releases energy as light. Which of the above labeled pieces of the reaction is the substrate?