Metabolic Flashcards
What enzyme converts D-Glucose -> Glucose-6-phosphate
Hexokinase
How many molecules of ATP and NADH and pyruvate are made via glycolysis
2 net molecules ATP (2 required, 4 produced)
2NADH
2 Pyruvate molecules
What enzyme converts pyruvate to lactate
Lactate dehydrogenase
What enzyme converts pyruvate to alanine
Alanine transaminase
Which GLUT transporter transports glucose to the brain
GLUT1
What GLUT transporter transports glucose to muscle and fat
GUT4
What glucose transport transports glucose to kidney/liver/pancreas
GLUT 2
What enzyme converts glucose –> glucose 6 phosphate
Hexokinase
What base molecule makes up glycogen and what does it connect to
Gluogenin
UDP Glucose
Which enzyme elongates the glycogen chain
Glycogen synthase
In a glycogen molecule
-what enzyme makes branches and what is the bond
-what enzyme elongates the chain and what is the bond
-Branching enzyme; a1-6 glycosidic bond
-Glycogen synthase; a1-4 glycosidic bond
What enzyme converts Glucose1phosphate to Glucose-6-phosphate
Phosphoglucomutase
What enzyme allows Glucose-6-phosphate to be relased into the blood
What organs is it found
What organ is it NOT found in
Glucose-6-phosphatase
Liver/Kidney/GIT
Not found in muscle
What pathway is used in the liver and RBC for glucose metabolism and to protect against oxidate stress
Pentose Phosphate pathway
What glycogen storage defect is due to a deficiency in glucose-6-phosphotase
von Gierke Disease- type 1
What causes Glycogen storage disease type 1: von Gierke disease and what are the symptoms
Glucose-6-phosphatase enzyme deficiency
Cannot convert G-6-P to free glucose so G-6-P builds up in cells
-hypoglycaemia
-G-6-P is shunted down glycolysis pathway to make pyruvate. Pyruvate converted ot
-Lactate (LDH)
-Alanine (ALT)
-Fatty acids –> hyperlipidaemia
Also get increased shunting of G6P down the pentose phosphate pathway –> increased purine synthesis –> increased uric acid
Conclusion
-Hypoglycaemia
-High lactate
-hyperlipidaemia
-Hyperalbuminaemia
-High uric acid
What can Glucose-6-phosphate become
glucose
Glycogen
Pyruvate–> alanine, fatty acids, lactate
Pentose phosphate pathway –> purine and pyridines –> urate
What features would you see in a child with GSD Type 1
what features on investigations
Hypoglycaemia –> seizures
Hepatomegally
Doll like facies + thin limbs
FTT
Investigations
-low BSL
-high lactate
-high alanine
-hyperlipidaemia
-hyperuraemia
-Liver biopsy: universal distension of hepatocytes with glycogen and fat
What foods should be avoided in von Gipple disease
Fructose
Galactose
What is the role of glucose-6-phosphate translocase
Glucose 6 phosphate is taken up into the ER
Dephosphorylated to glucose by glucose-6-phosphatase
Glucose-6-phosphate translocase allows the transport of G6P into the endoplasmic reticulum
SLCA gene is associated with what glycogen storage disease defect
GSD Type 1b: Glucose-6-phosphate translocase deficiency
What distinguishes type 1a via type 1b glycogen storage disease
Type1a= Von Gierke Disease- glucose-6-phosphatase deficiency
Type1b = Glucose-6-phosphate transferase deficiency due to SLCA gene
Both have accumulation of Glucose-6-phosphate –> hyperalanine, hyperlipidaemia, high lactate, hypoglycaemia
Type1b also has neutropenia and manage as per type 1a but also use prophylactic cotrimoxazole
hypoglycaemia, lactic acidosis, hyperuricemia, hyperlipidaemia
what is the disease
Glycogen storage disease type 1a or b
What is Pompe a disease of what enzyme
Where does glycogen accumulate
What are the symptoms
Pompe= GSD type 1
-disease of acidic alpha glucosidase (to break a1-4 and a-1-6 glycosidic binds)
-Accumulates in the liver and in muscle (skeletal, heart and smooth muscle)
Sx
-Hepatomegaly/ liver enlargement likely 2 to heart failure
-Cardiac: enlarged heart, Hypertrophic cardiomyopathy
-Skeletal: hypotonia, proximal myopathy in juvenile disease
-Smooth muscles of blood vessels and organs
-Enlarged tongue
Involvement of the diaphragm can cause respiratory distress