What extracellular enzyme hydrolyzes TAG’s?
lipoprotein lipase (LPL)
What is LPL produced by?
fat and muscle cells
Where does hydrolization of TAG occur?
capillary beds
Exercise can result in an increase in what enzyme?
skeletal muscle LPL
What is the most common storage site for TAG?
adipose tissue
FA synthesis is stimulated by what?
insulin
What does insulin strongly inhibit that hydrolyzes stored TAG?
HSL
During fasting insulin is ______ and glucagon is _______
decreased, increased
What gets lipids into the target cell?
LPL
What lipase converts TAG to DAG?
ATGL
What lipase converts DAG to MAG?
HSL
What lipase converts MAG to FFA?
MGL
Intracellular lipase is stimulated by?
Hormones (epinephrine, glucagon, adrenocorticotropic)
Once a hormone attaches to the Beta-1 receptor on a TAG, what phosphorylates TAG to the active form?
cAMP and adenyl cyclase (2nd messengers)
What would PKA stimulate when associate with a TAG?
lipolysis (fat burning)
Besides lipolysis, what does PKA stimulate in catabolism of TAG?
HSL
If HSL is inhibited, what other lipase is also inhibited?
ATGL
What enzyme converts G-3-P to DHAP
G-3-P dehydrogenase
Where in the cell does beta oxidation occur?
mitochondrial matrix
When the FA first enters the cell, what is activated by to form Acyl-CoA?
Acyl-CoA synthetase
What is the location of a FA activated to Acyl-CoA?
outer mitochondrial matrix
What is considered the rate limiting step of beta oxidation?
CPT
What inhibits CPT?
Malonyl-CoA
What is the main enzyme of CPT?
acyl-carnitine translocase
What 2 additional enzymes are required for unsaturated FA degradation?
reductase, isomerase
Isomerase will break down _____ numbered double bonds
odd
Reductase AND isomerase will break down _____ numbered bonds
even
What cofactor couples with reductase in unsaturated FA degradation?
NADPH
In unsaturated FA degradation, isomerase will convert what enzyme?
trans-Enoyl CoA
What is the final product of unsaturated FA degradation?
propionyl CoA
What does propionyl CoA get converted to?
succinyl CoA
What is the location of ketogenesis?
mitochondrial matrix of the LIVER
What is considered the rate limiting step of ketogenesis?
HMG CoA synthase
What would stimulate mitochondrial HMG CoA synthase?
prolonged fasting, no/low carbs
Cytosolic HMG CoA synthase is used in what pathway?
cholesterol synthesis
No carbs, low ATP, and in the liver would stimulate what pathway?
ketogenesis
Besides low carbs/starvation, what would create a high concentrations of ketones in the system?
accelerated Beta-oxidation and uncontrolled Type 1 diabetes
In ketogenesis, glucagon stimulates what process?
fat burning
In ketogenesis, glucagon inhibits what process?
liver glycolysis
In ketogenesis, Acetyl CoA inhibits enzyme?
pyruvate dehydrogenase
Functional ketone bodies are converted into what to be used to make energy?
acetyl CoA
What are the primary sites of glycogen storage?
liver and skeletal muscle
Where in the cell is glycogen stored?
cytosol
What enzymes breaks alpha(1-4) bonds?
glycogen phosphorylase
What is the coenzyme with glycogen phosphorylase?
pyridoxal phosphate
What is the product of glycogen phosphorylase breaking the alpha(1-4) bond?
glucose-1-phosphate
What enzyme converts glucose -1-phosphate to glucose-6-phosphate?
phosphoglucomutase
What enzyme removes outer 3 glucose molecules on glycogen?
glucosyl 4:4 transferase
What enzyme removes the last glucose of the branch?
amylo-alpha-1,6-glucosidase
What is the key regulatory enzyme of glycogenolysis?
glycogen phosphorylase
What hormones are involved in the regulation of glycogen breakdown?
glucagon, epinephrine and norepinephrine
What are the allosteric regulators of glycogenolysis?
AMP and calcium
On what tissue would glucagon have an effect?
the liver
On what tissues would epinephrine and norepinephrine have an effect?
muscle and liver
What is adenylyl cyclase activated by in glycogen breakdown?
glucagon, epinephrine and norepinephrine
What enzyme is stimulated by the presence of cAMP?
PKA/AMPK
In general, what does AMPK inhibit?
synthesis pathways
In general, what does AMPK stimulate?
breakdown pathways
What would activate glycogen phosphorylase?
AMP
What is a subunit of glycogen phosphorylase kinase complex?
calmodulin
What are the final products of AA catabolism when creating an alpha-keto acid?
ATP, Glucose, FA
What is the main site for AA catabolism?
liver
Where are branched chain AA more often catabolized?
skeletal muscle
What are the AA that skeletal muscle can oxidize?
LIV (branched) GAA (glutamate, aspartate, asparaine)
What coenzyme is required for transamination?
pyridoxal phosphate
What is the enzyme used to deaminate glutamate?
glutamate dehydrogenase
What cofactor is coupled with glutamate dehydrogenase?
NAD+
What is the a-ketoacid of alanine?
pyruvate
What is the a-ketoacid of aspartate?
oxaloacetate
What is the a-ketoacid of glutamine and glutamate?
a-ketoglutarate
What enzyme is used to stick an extra amino group on glutamate?
glutamate synthetase
What enzyme in the muscle turns glutamate into glutamine by adding a nitrogen/ammonia?
glutamine synthase
In the muscle, what hydrolyzes glutamine back to glutamate?
glutaminase
In skeletal muscle, what makes alanine from pyruvate?
ALT or glutamate-pyruvate transaminase (GPT)
What enzyme transfers an amino group from glutamate to oxaloacetate to make aspartate?
AST or glutamate-oxaloacetate transaminase (GOT)
What does the first NH3 on urea come from?
glutamate dehydrogenase (GDH)
Where does the second NH3 on urea come from?
aspartate aminotransferase (AST)
What enzyme would create carbamoyl phosphate from Co2, NH3, and 2 ATP?
carbamoyl phosphatase
Where in the cell is carbamoyl phosphatase active?
mitochondrial matrix
What 2 places in the cell does the urea cycle take place?
cytosol and mitochondrial matrix
What can be considered the prep step of the urea cycle?
carbamoyl phosphatase
What enzyme cleaves off 2 amino groups to create urea?
arginase
A-ketoglutarate entering krebs cycle can be called what process?
anaplerosis
Glutamate concentrations in the plasma during exercise tend to?
decrease
Alanine concentrations in the plasma during exercise tend to?
increase
What is over 90% of muscle amino acid uptake after a meal?
LIV and glutamate
What amino acids are released in amounts MORE than they are taken in?
glutamine and alanine (transporters)
What amino acids are released in LESS amounts than they are taken in?
LIV GAA
What energy charge stimulates oxidation of amino acids?
low energy
What enzyme does high energy and plenty of glycogen storage inhibit?
PFK (glycolysis)
What enzyme does glucose-6-phosphate accumulation inhibit?
hexokinase
What stimulates glucokinase?
insulin and fructose
After going through the fructose-1-phosphate pathway, how will fructose enter glycolysis?
as G-3-P
Where in the cell does FA synthesis occur?
cytosol
What is the main coenzyme of FA synthesis?
NADPH
What enzyme combines acetyl-CoA and oxaloacetate to make citrate?
citrate synthase
What enzyme creates OAA and Acetly-CoA from cytosolic citrate?
citrate lyase
What enzyme creates Malonyl CoA from Acetyl CoA?
Acetyl CoA Carboxylase (ACC)
What is the rate limiting step of FA synthesis?
Acetyl CoA Carboxylase (ACC)
What is the final step of FA synthesis?
Palmitate
Which 2 steps of FA synthesis will use NADPH?
the reduction steps
What enzyme will release Palmitate from FA synthesis?
palmitoyl thioesterase
What coenzyme is required for elongases?
NADPH
What enzyme adds double bonds to Palmitate?
desaturases
