---
title: "Colorful Mystery Solved: Scientists Discover Enzyme That Makes Urine Yellow"
date: 2024-01-03T13:00:00-05:00
author: University of Maryland
canonical_url: "https://today.umd.edu/colorful-mystery-solved-scientists-discover-enzyme-that-makes-urine-yellow"
section: Articles
---
# Colorful Mystery Solved: Scientists Discover Enzyme That Makes Urine Yellow

*January 3, 2024* — by [Emily C. Nunez](/author/emily-c-nunez)


> Finding Could Illuminate Future Studies of Gut Health and Inflammatory Bowel Disease


Researchers at the University of Maryland and National Institutes of Health have identified the enzyme responsible for giving urine a yellow hue, and it’s more than a matter of idle curiosity or grade-school giggles.  
  
The microbial enzyme known as bilirubin reductase was introduced in a [study](https://www.nature.com/articles/s41564-023-01549-x) published Wednesday in the journal *Nature Microbiology,* paving the way for further research into the gut microbiome’s role in ailments like jaundice and inflammatory bowel disease.  
  
“It’s remarkable that an everyday biological phenomenon went unexplained for so long, and our team is excited to be able to explain it,” said lead author Brantley Hall, an assistant professor in UMD’s Department of Cell Biology and Molecular Genetics.


*diagram showing bilirubin, conjugated bilirubin, urobilinogen, stercobilin, urobilin*




**Topics:** [Research](https://today.umd.edu/tags/research)


**Tags:** [Cell Biology and Molecular Genetics](https://today.umd.edu/topic/cell-biology-and-molecular-genetics), [Research](https://today.umd.edu/topic/research)


**Units:** [College of Computer, Mathematical, and Natural Sciences](https://today.umd.edu/topic/college-computer-mathematical-and-natural-sciences), [University of Maryland Institute for Advanced Computer Studies](https://today.umd.edu/topic/university-of-maryland-institute-for-advanced-computer-studies)