Galactose Flashcards
Galactose gets used by the
liver
brain
First enzyme of galactose metabolism
galactokinase
converts galactose to galactose-1-phosphate
uses 1 ATP
What is the importance of galactokinase
it locks galactose in the liver and brain
What is the most important enzyme of galactose metabolism
Galactose-1-phosphate uridyl transferase
Galactose-1-phosphate uridyl transferase needs what two substrates
Galactose-1-phosphate
UDP-glucose (glucose donor)
What does Galactose-1-phosphate uridyl transferase do
turns galactose-1-phosphate to glucose 1-phophate
makes UDP-galactose (galactose donor) from UDP glucose
What happens in galactose kinase deficiency
early in life cataracts
What happens in Galactose-1-phosphate uridyl transferase deficiency
cataracts early in life diarrhea/vomiting after lactase ingestion lethargy liver damage hyperbilirubinemia hypoglycemia jaundice mental retardation
caused by build up of galactose 1-P in the liver and brain
Why is galactokinase deficiency so mild?
If galactose can’t be trapped in the liver or brain it will go back out into the blood
Why do you see cataracts in galactosemias
Build up of galactose in the blood
galactose can go to the lens
trapped in lens by aldose reductase –> Galactitol
How does Galactitol cause cataracts
It is osmotic
causes the lens to swell and causes cataracts
How to diabetics get cataracts
Glucose taken into the lens
Aldose reductase converts to sorbitol
causes water to come in and the lens swells
