Metabolism Flashcards
Where do FA synthesis, HMP shunt, steroid synthesis, and cholesterol synthesis occur?
Cytoplasm
What cycles occur in both the mitochondria and cytoplasm?
Urea
GLuconeogenesis
Heme
What is the rate limiting enzyme of glycolysis? Regulators?
Phosphofructokinase 1
+= F2,6-BP, AMP
- = CITRATE, ATP
What is the rate limiting enzyme of Gluconeogenesis? regulators?
F-1,6-BPase
+ = ATP,
- = F2,6BP, AMP
What is the rate limiting enzyme of TCA cycle? regulators?
Isocitrate dehydrogenase
- = NADH
What is the rate limiting enzyme of HMP shunt?
G6PD
- = NADPH
What is the rate limiting enzyme of de novo pyrimidine synthesis?
Carbamoyl phosphate synthetase II
What is the rate limiting enzyme of de novo Purine synthesis?
Glutamine-PRPP amidotransferase
- = IMP, AMP, GMP
What is the rate limiting enzyme of Urea cycle?
Carbamoyl phosphate synthetase I
+ = N- acetylglutamate
What is the rate limiting enzyme of FA synthesis? regulators?
Acetyl-CoA carboxylase
- = Palmitoyl CoA, glucagon
What is the rate limiting enzyme of FA oxidation?
Carnitine acytransferase I
- = Malonyl CoA
What is the rate limiting enzyme of Ketogenesis?
HMG-CoA synthetase
What is the rate limiting enzyme of cholesterol synthesis? regulators?
HMG CoA reductase
+ = Insulin, T3
What enzyme is def in SEVERE galactosemia?
Galactose-1-phosphate uridyltransferase
What enzyme is def in von Gierke’s disease?
Glucose-6-phosphatase= turns G6P–> Glucose for release during gluconeogenesis
What enzyme is deficient in Fructose intolerance?
Aldolase B = Fructose-> G3P/ DHAP
What enzymes require Thiamine as a cofactor?
Transketolase (ribulose 5P->F6P) Pyruvate dh (pyruvate-> acetyl CoA) aKetogluterate dh (aketo--> Succinyl-CoA)
Difference btwn Hexokinase & Glucokinase?
Hexo= muscles/Fat, low Km, low Vmax, uninduced by insulin Glucokinase= Liver/ Pancreatic beta cells, High Vmax/Km
What molecules carry CO2, 1 carbon units, or methyl group?
CO2= Biotin
1carbon unit= THF
Methyl group= SAM
What are the KETOGENIC AAs?
Lysine
Leucine
benign asymptomatic enzyme def with Fructose appearing in urine?
Fructokinase def
Enzyme def causing Hypoglycemia, Jaundice, cirrhosis, vomiting and build up of F-1-P?
Aldolase B def= Fructose intolerance
Enzyme def causing Galactitol accumulation, galactose in urine and infantile cataracts?
Galactokinase Def
Infant with failure to thrive, jaundice, Hepatomegaly, cataracts, and retardation, with Excess Galactitol accumulation?
Galactose 1-phosphate Uridyltransferase def
Def in Galactosemia vs Fructose intolerance?
Fructose= Aldolase B Galactose= Uridyltransferase
What cells have only Aldose reductase and NOT sorbitol dehydrogenase?
Retina
Schwann
Kidney
What are the Ketogenic & glucogenic essential AAs?
Keto= Leu/ Lys Gluco= Met, Val, His
What is the treatment for Hyperammonemia?
Low protein
Lactulose to Acidify GI and trap NH4
What is Ornithine transcarbamyolase def?
MC Uraa cycle enzyme def= Hyperammonia + High Orotic acid in blood/urine
**Infant with Tremor, somnolence, vomiting, and lactic acidosis.
Production of DA/NE/ Epi require what 2 AAs?
Pheylalanine–> Tyrosine-> DA–> NE –> EPi
Conversion of Dopa to DA requires?
DA–> NE requires?
NE–> Epi requires?
B6
Vit C
SAM
How is glycogenesis and muscle activity coordinated?
Ca/ Calmodulin in muscle activate Glycogen phosphorylase to breakdown glycogen
Epi & glucagon have what similar actions?
increase cAMP
activate PKA
activate Glycogen phosphorylase
Function of ApoE?
remnant uptake (all but LDL)
Function of ApoA1?
Activate LCAT on HDL
Function of ApoCII
Lipoprotein lipase cofactor (HDL, VLDL, chylomicrons)
Function of ApoB48?
chylomicron secretion
ApoB100?
Binds LDL receptor
