Galactose is an aldohexose, so it is an aldehyde that is made up of 6 carbons.
As we have mentioned in the previous posts, galactose is one of the two simple sugars commonly found in lactose sugar. The other simple sugar found is glucose.
When a patient that has galactosemia consumes lactose, the body produces lactase to digest lactose into glucose and galactose.
In normal metabolism: When there is galactose produced in the body, it will be transported to the liver. In the liver, galactose will then be converted to glucose which is a source of energy for the body.
1. Galactose is first phosphorylated by the enzyme GALK. An ATP molecule is needed for this process. Galactose-1-phosphate and ADP is produced.
2. The phosphorylated galactose is then converted to glucose-1-phosphate with the help of the enzyme GALT and UDP glucose. UDP galactose is also produced in the process.
3. UDP galactose is converted to UDP glucose by the enzyme GALE. This is to ensure that there is sufficient amount of UDP glucose so that the process of conversion of galactose-1-phosphate to glucose-1-phosphate can take place.
In the case of GALACTOSEMIA:
Type 1: deficiency of GALT enzyme
- Galactose can be phosphorylated to galactose-1-phosphate by GALK enzyme. However, the phosphorylated galactose cannot be converted to glucose-1-phosphate due to the lack of the GALT enzyme.
Type 2: deficiency of GALK enzyme
- The first step of phosphorylation of galactose cannot take place without GALK enzyme.
Type 3: deficiency of GALE enzyme
- UDP galactose cannot be converted to UDP glucose as there is a lack of enzyme GALE. As UDP glucose is needed for the conversion of phosphorylated galactose to glucose-1-phosphate, without GALE, there will not be enough UDP glucose to aid in the conversion.
Content Reference:
Picture references: http://www.food-info.net/images/lactase.jpg
The blog has many detailed explanations and pictures to help people understand this condition more easily,along with case studies that show how people cope with this disease. Well done! :D
ReplyDelete-FM and Daryl