Lecturio - Bilirubin Metabolism Flashcards
Where does heme catabolism begin?
Spleen
Identify
1/ Heme
2/ Biliverdin
A - Heme oxygenase
Damage blood cells are recognized by ___
the speen
Increased activity of heme oxygenase stimulates _____
ferritin production
Identify
1/ Biliverdin
2/ Bilirubin
A - Biliverdin reductase
What is the consequence of the reduction at the center of this reaction?
Reduction at the center joint
- breaks conjugation
- allows flexibility in molecule
How does ROS reduction cycle work?
Structural features of biliverdin reductase
1/ Serine-threonine-tyrosine kinase
2/ Leucine zipper domain
5 functions of biliverdin reductase
1/ Affects insulin signaling
2/ May block movement of glucose into cell
3/ May play role in insulin resistance
4/ Acts as transcription factor
5/ May control cAMP-related genes
Which enzyme catalyze this reaction?
Glucoronyltransferase
Identify
1/ Bilirubin
2/ UDP-glucuronic acid
A - Bilirubin diglucoronide
B - UDP
The liver adds glucuronic acid to bilirubin for ___
export to the bile
What are the 2 forms of Bilirubin?
1/ Soluble (conjugated)
2/ Insoluble (unconjugated)
3 Characteristics of Soluble (conjugated) form of Bilirubin
1/ Conjugated to glucuronic acid
2/ Dissolves in water
3/ Eliminated through bile/feces/urine
3 Characteristics of Insoluble (unconjugated) form of Bilirubin
1/ No glucuronic acid links
2/ Binds to albumin
3/ Not filtered by kidneys
The cause of jaundice?
Arising from excess bilirubin
What can conjugated bilirubin indicate?
Liver disease
