8. Biochemisty II p152-162

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NAD+/NADPH: pg152
it is used in catabolic processes to carry reducing equivalents: NAD+ (--> NADH)
NADPH is used in (name 3): 1. anabolic process (supply reducing equivalents); 2. respiratory burst; 3. P-450
the HMP shunt and the malate dehydrogenase reaction produce_____: NADPH
oxygen dependent respiratory burst: pg 152
what enzyme converts O2--> O2ÿ: NADPH oxidase (with NADPH)
what enzyme converts O2ÿ--> H2O2: superoxide dismutase
what enzyme converts H2O2 --> HOClÿ: myeloperoxidase
what enzyme converts H2O2 --> H2O: catalase (also requires GSH--> GSSG)
hexokinase vs glucokinase: pg 152
where is hexokinase found: throughout the body
where is glucokinase found: mainly in the liver
the affinity (Km) and capacity (Vm) of glucokinase (compared to hexokinase) is: lower affinity (higher Km) and higher capacity (higher Vm)
glycolysis regulation, irreversible enzymes: pg153
what is the irreversible enzyme and the regulator of the reaction: D-glucose ---> Glucose-6-phosphate: hexokinase (glucokinase in the liver);it si negatively regulated by G6P
what is the irreversible enzyme and the regulator of the reaction: fructose-6-P ---> fructose-1,6-BP: phosphofructokinase (rate limiting step of glycolysis); up-regulated by AMP, fructose-2,6-BP; down regulated bu ATP; citrate
what is the irreversible enzyme and the regulator of the reaction: PEP ---> pyruvate: pyruvate kinase; up regulated by fructose-1,6-BP; down regulated by ATP, alanine
what is the irreversible enzyme and the regulator of the reaction: pyruvate ---> acetyl-CoA: pyruvate dehydrogenase. Down-regulated by ATP, NADH, acetyl CoA
glycolytic enzyme deficiency: pg153
what are the 7 glycolytic enzyme deficiencies associated with hemolytic anemia: hexokinase, glucose phosphate isomerase, aldolase, triosephosphate isomerase, phosphate glycerate kinase, enolase, pyruvate kinase
how do RBCs metabolize glucose: anaerobically (depend solely on glycolysis)
pyruvate dehydrogenase complex: pg153
this complex contains 3 enzymes. What are the 5 cofactors it requires?: the first 4 B vitamins +lipoic acid [B1(thiamine, TTP); B2 (FAD); B3 (NAD); B5(pantothenate-->acetyl CoA) ]
what is another complex that works in a similar way: alpha ketogluterate dehydrogenase
what is the reaction it catalyzes: pyruvate + NAD + CoA ---> acetyl-CoA + CO2 + NADH
pyruvate dehydrogenase deficiency: pg153
what are the only purely ketogenic amino acids: Leucine, Lysine
lactic acidosis in this condition is due to backup of _____: alanine and pyruvate (can be seen in alcoholics)
what is the Tx for this condition: intake of ketogenic nutrients (high fat content)
what is one of the most important findings associated with this condition: neurological defects
Pyruvate Metabolism: P. 154
Pyruvate can be metabolized into four compounds. Name them.: Lactate, Acetyl-coA, Oxaloacetate, and Alanine - remember, if you Love pyruvate, you'l be AOA.
When is pyruvate generated?: Anaerobic metabolism, mainly in muscles. Remember - lactic acid makes muscles sore.
What role does Alanine play in transport?: Alanine carries nitrogen groups from muscles to liver.
How many ATP equivilnets are there between glucose and pyruvate?: 6
Where is Oxaloacetate used?: Oxaloacetate and Acetyl-CoA are both elements of the TCA cycle. Oxaloacetate can alos be used in gluconeogenesis
How many ATP equivilents does ti take to turn Pyruvate into Alanine?: Trick question. None. Alanine is the only pyruvate product that does not require energy.
Cori Cycle: P. 154
What is the Cori cycle?: The process that gets lactic acid from cells who burn glucose anaerobically to the liver, where gluconeogenesis is preformed to send glucose back to those cells.
What two types of tissue produce lactate most frequently?: Muscles working anaerobically, and RBCs (no mitochondria)
How many ATPs do cells get burning glucose to pyruvate?: 2
How may ATP does it take to get glucose from pyruvate in the liver?: 6
Given that you lose 4 ATP in each cycle, why is this a useful process?: Allows muscles to continue to function anaerobically if you need to and are low on blood glucose.
TCA Cycle: P. 154
Name the molcules in the TCA cycle.: Citrate, Isocitrate, Alpha-Ketogluterate, Succinyl CoA, Succinate, Fumerate, Malate, Oxaloacetate.
How to remember this?: Cindy Is Kinky So She Fornicates More Often.
What is the net gain of ATP?: 12 per cycle of the TCA, so 24 per glucose
What things are formed per pyruvate?: 3 NADPH, 1 FADH2, 1 GTP, and 2CO2.
How is this cycle regulated?: unless there is suficient ADP it will not run
Which enzyme complex in the cycle requires co-factors?: The Alpha-ketogluterate dehydrogenase complex.
What factors does it require?: 5 - the same ones that are required by the pyruvate dehyrodgenase complex
Which areÂ….?: B1 (thiamine), B2 (riboflavin, FAD), B3 (Niacin, NAD), B5 (pantothenate) and Lipopoic acid
Electron Transport Chain and Oxidative Phosphyrylation: P. 155
What does the electron transport chain do?: The ETC carries high energy electrons from NADH and FADH2 to oxegen
How does this generate ATP?: Each cytochrome complex pumps H+ into the intermembrane space. ATP generation is coupled to the H+ gradient
Where are these enzymes located?: The inner mitochondrial membrane
What is the effect of ETC inhibitors?: By stopping the ETC they cuase the loss of the H+ gradient, which stops ATP syntesis
Name four ETC inhibitors.: Cyanide, Anitmycin A, rotenone, and CO
What is the effect of ATPase inhibitors?: By stopping the enzyme that uses the H+ gradient to produce ATP, the H+ gradient increases and the ETC stops.
Name one.: Oligomycin
What are the effects of uncoupling agonist?: They increase membrnae permeabliity, so you lose the H+ gradient, so the ETC works harder, and you use more oxegen, wihtout making more ATP.
What are the clinical comsequences of this?: Since the by-product of the ETC chain is heat, when the ETC is uncoupled and therefore unregulated, you get excess heat production and fever.
What common drug overdose causes this?: Asprin and other salycilates
Gluconeogenesis, Irreversible Enzymes: P. 155
What is gluconeognesis?: Since glycolysis is a very energetically favorable reaction, special enxymes are required to get over the energy hump and make glucose from pyruvate.
How many enzymes are unique to this reaction?: 4. The other 7 enzymes are the same ones used in glycolysis
****What are the four unique enzymes of gluconeogenesis?: Pyruvate Carboxylase, PEP Carboxykinase, Fructose-1-6-bisphosphanate, and Glucose-6-phosphate, Remember: Pathway Produces Fresh Glucose.
What does Pyruvate Carboxylase do?: Pyruvale into oxaloacetate
Where does this reaction take place?: In the mitochondria. Remember, this is where the pyruvate is, asince otherwise it would eb going into the TCA cycle
What happens next?: Oxaloacetate is turned into malate, which is transferied into the cytosol
Why is this imporntat?: If gluconeogneeis and glycolysis happened int eh same space, they would cancel each other out.
Where does the rest of the cycle take place?: In the cytosol
What tissues have these enzymes?: liver, kidney, and intestinal epithlium.
What happens if you lack one of these?: Hypoglycemia if you do not eat frequently
Give an example.: Von Gierke's Disease (lack of Glucose-6-phosphatase)
Pentose Phosphate Pathway (HMP Shunt): P. 155
Is any ATP produced or consumed in this?: No
Is it reverisble?: Yes. The direction of flwo is controled by the metablic needs of the cell.
What does this pathway produce?: Ribose-5-P for nucliotides synthesis and NADPH for RBC metabolism and fatty acid production
Where does it take place?: In the cytosol.
What tissues have this pathway?: Places that make fatty acids or seteroids, so liver, mammary tissue, and adrenal cortex, as well as RBC
Glucose-6-P Dehydrogenase Deficiency: P. 156
G6PD is part of what pathway?: It is the rate limiting step in the PPP (aka HMP) shunt.
What molecule is decreased if this enzyme is inactive?: NADPH
What is this a problem?: NADPH is necissary to reduce glutathione, which is vital in detoxification of free radicles and oxidizing agents.
What cells are most sensitive to this kind o damage?: RBCs
What kind of disease is caused by a lack of G6PD?: Hemolytic anemai, triggered by oxidative stress.
What consititues oxidative stress?: TB drugs, Fava beans, sulfonamides
How is this disorder passed on?: X- linked recessive.
Where is this prevelent?: Black and mediteranean populations
Histoligically, what will be seen?: Heinz bodies (clumped hemoglobin)
Disorders of Fructose Metabolism: P. 156
Fructose is central in what pathways in the liver?: Fructose is found in the glycolysis and gluconeognesis pathway.
What is the first step in putting fructose into each of these pathways?: Aldolase B splits fructose-1-P ito Glyceraldehye-3-P
Therefore, a metabloic problem *before* the aldolase will cuse whqat disorder?: Fructose will accumulate, and spill into the urine
What is this called?: essential fructosuira
What is the enzyme involved?: frucokinase (puts a P on fructose)
Is this a dangerous disorder?: no, it is benign, you just have high levels of fructose in your blood and urine. Asymptomatic.
What will happen if Aldolase B is impaired?: Fructose-1-P will build up in the liver
Is this a problem?: Yes. Phophate is used up, and glycogenolysis and gluconeogensis are both impaired.
What are the symptoms?: cataracts, hepatoslenomegaly, and mental retardation
What is the treatment?: Decrease fructose and sucrose intake
****What is the naem of this disorder?: Fructose intolerence
Disorders of Galactose Metabolism: P. 157
What two steps does Galactose have to go through to enter glycolysis?: Glactokinase turns galactose into galactose-1-P, and then Galactose-1-P uridyl transferase turns that into glucose-1-P
If galactokinase is imparied, what happens?: Galactose builds up in the blood and spills in the urine, but there is no build up of the toxic compound galactose-1-P
****Is this dangerous?: No
What happens if Galactose-1-P uridyl tranferase is impaired: Glactose builds up int eh blood, and spills into the urine. There is a build up of the toxic metabolite glactose-1-P
What is this disease called?: Galactosemia
Is is dangerous?: Yes
What is the treatement?: reduceing galactose in diet
How do you do this?: Galactose comes from lactose, so limit dairy
Lactase deficiency: P. 157
Where is lactase normally found?: intestinal brush border
Therefore, if it is missing, what is the main symptom?: gas, bloating, and osmitic diarrhea
Is this common?: Yes.
More in what populations?: Asians and black more than europeans
Esential Amino Acids: P. 157
What is a neumonic for the essential amino acids?: PriVaTe TIM HALL - Phe, Val, Trp, Thr, Ile, Met, His, Arg, Leu and Lys.
Which amino acids are purely ketogenic?: Leu and Lys
Which amino acids are purely both ketogeneic and glucogenic?: Tyrosine, Isoleucine, Phe and Try
What a.a.'s are purely glucogenic?: Anything that is not one of the six above.
Wath two amino acids are essential during growht, but not he rest of the time?: Arg and His
Acidic and Basic Amino Acids: P. 157
What two a.a.'s are acidic and negativly charged at body pH?: Asp (asparatic acid) and Glu (glutamic acid)
What two a.a.'s are basic and positivly charged at body pH?: Arginine and Lysine (rememebr they are th two with NH3 groups.
How does the body use the positive charge on Arg and Lys?: Histones, which bind to negativly charged DAN are high in these a.a.
Transport of Amonium by Alanine and Glutamine: P. 158
Whay does your body produce amonium?: It comes from the NH3 group of amino acids which are being broken down
Where does this happen?: Everywhere in the body
What is the enzyme that transfers the NH3 group: Amino transferases (ex:AST (asparatate amino trnasferase), ALT (alanine amino transferase)
What two molecules is NH3 transferred between?: It moves from an amino acid to alpha=ketogluterate, making it glutamate.
****Is this reaction reversible?: Yes. Glutamate functions as a resevoir, so NH# can be made into urea, or is can give NH3s for a.a. production
Where are these enzymes found?: Inside the cells, so if they are in the blood that is a sign of tissue damage (most in liver and muscle)
Once the NH3 has been added to alpha-ketoglutamate and you have glutamate, what are two pathways it can take from their?: The NH3 can be transferred to pyruvate to form alanine, which is then trasfered int eh blood to the liver to join the urea cycle. Or, glutamate can, with NADPH, release it directly into the blood as amonium.
What is the difference between pyruvate and alanine?: an NH3 group.
Urea Cycle: P. 158
What is the function of the urea cycle?: a molecule that hleps dispose of excess nitrogen.
What tissue does it occur in?: Liver
What part of the cell?: The first two reactions in mitochondria, the rest in cytoplasm
How many molecules of nitrogen are in urea?: Two
What molecules do they come from?: one if free amonium, the other from asparatate.
What is the immediate precursor of both moleulces?: Glutamate provides free amonium (see aboe), and is also converted into aspartate.
What are the reactions?: Ornithine into Carbamoyl phosphate into citruline, add asparate becomes arginosuccinate, fumerate leaves, leaving arginine, produces urea and ornithing again.
****MNeumonic for this?: Ordinarrily Careless Crappers Are Also Frivolous About Urination.
Is this reversible?: No, highly irreversible
Which reactions happen in the mitochondria?: Carbamoyl phsophate is formed there, and added to ornithine to make citruline.
Amino acid dervatives: P. 158
What a.a. does Histamine come from?: Histadine
What a.a. does creatinine come from?: arginine
What a.a. does throxine come from?: Tyrosine (which comes from phenylalanine)
What a.a. does niacin come from?: Tryptophan
What a.a. does heme come from?: The porphyrin comes from glycine
What a.a. does melatonin come from?: Tryptophan
What a.a. does NE and Epi come from?: Dopamine, which comes from tyrosine
What a.a. does Urea come from?: arginine (the NH3 is donated by glutamate)
What a.a. does melanin come from?: Dopamine, which comes from tyrosine
What a.a. does dopamine come from?: Tyrosine (which comes from phenylalanine)
What a.a. does seratonin come from?: Tryptophan
What a.a. does Nitric oxide come from?: Arginine
What a.a. does NADP come from?: Niacin, which comes from tryptophan
Phenylketonuria: p. 159
What is the primary problems in this disease?: two possible: Can't make homocysinte into cystine, or can't make homocystine into methionine.
What does this cause?: Tyrosein becomes essentail and phenylalanine builds up in blood and spills into urine.
What are the clinical findings?: Dark urine and connective tissue
Treatement?: Restirction phenylalanine, ingest tyrosine
Alkaptonuria: P. 159
What enzyme?: homogentisic oxidase
Is the benign?: Yes. Can have arthralgias.
Albinism: P. 159
Causes?: Can be lack of tyrosinase or that nerual crest cels failed to migrate and you have no melanocytes.
Risks it causes?: Lack of melanin leads to risk of skin cancer
Homocystinuria: P. 159
Results of this defect?: If it is homocystine to cystine that is impaired, cystine is essential. IT can cause mental retardation, osteoperosis, and lens dislocation.
Treatment?: Acetazolamide
What co-factor is used to change homocystine to methionine?: Vitamine B12 and tetrahydrofolate
Can increased Vit B 12 be theraputic?: Yes, if the problem is the affinityof the enzyme for its co-factors
Cystinuria: P. 159
What is the primary problem in this disease?: block in degredation of branches aa
What a.a. are effected?: COLA: Cystine, Ornithine, Lysine, and Arginine
What are the clinical effects?: Kidney stones made of cystine (radiolucent)
How does it work?: alkalinizes the urine
Maple Syrup Urine Disease: P. 159
Which are those?: I Love Vermont Maple Syrup: Ile, Leu, Val
What are the clinical signs?: Urine smells like maple syrup, leads to mental retardatrion, CNS defects, and death.
Purine salvage deficiencies: p. 160
Adensoine deaminase deficiency leads to what condition?: SCID
SCID affects T cells, B cells, or both?: Both
Lesch-Nyhan syndrone (LNS) results in inability to salvage which nucleotide?: Purine
Lesch Nyhan Syndrome has which inheritance pattern?: X-linked recessive
Result of LNS is excess production of __________.: Uric acid (gout is one finding in LNS)
Fatty acid metabolism sites: p. 160
Fatty acids are synthesized in the _________.: Cytosol
Fatty acids are degraded in __________.: Mitochondria (where products will be consumed)
Fatty acid entry into cystol is via ________.: Citrate shuttle
Fatty acid entry into mitochondria is via _______, which is inhibited by _________.: C2
Liver: Fed state vs. fasting state: p. 161
In fasting state, fatty acids are ultimately converted to what?: Ketone bodies
Glycogen storage diseases: p. 161
What is the end result of all glycogen storage diseases?: Abnormal glycogen metabolism and accumulation of glycogen in cells
Type I is also known as _______.: Von Gierke's disease
What is the deficiency in type I/Von Gierke's disease?: Glucose 6-phosphatase deficiency
Findings in type I/Von Gierke's disease are ________ and _________.: Severe fasting hypoglycemia, excess glycogen in liver
Type II is also known as ______.: Pompe's disease
What is the deficiency in type II/Pompe's disease?: Lysosomal alpha-1,4 glucosidase deficiency
Findings in type II/Pompe's disease are _________ and _________.: Cardiomegaly, systemic findings (liver, muscle)
****Type III is also known as _____.: Cori's
What is the deficiency in type III/Cori's?: Debranching enzyme alpha-1,6-glucosidase deficiency
Type IV is also known as _______.: McArdle's disease
What is the deficiency in type IV/McArdle's disease?: Skeletal muscle glycogen phosphorylase deficiency (McArdle's = Muscle)
Result of type IV/McArdle's disease is _________.: Increased glycogen in muscle, but can't be broken down (results in cramps, myoglobinuria)
What is the pneumonic to remember types I through IV?: Very Poor Carbohydrate Metabolism
Ketone bodies: p. 161
What are two incidences when ketone bodies found in urine?: Prolonged starvation, diabetic ketoacidosis
Ketone bodies are made by _______.: HMG-CoA
Ketone bodies are metabolized by the brain to 2 molecules of ________.: Acetyl-CoA
Insulin: p. 161
Where is insulin made?: Beta cells of pancreas
Insulin does not affect glucose uptake in _____, ______, or _______.: Brain, RBCs, hepatocytes
****Required for uptake of glucose by ______ and _______.: Adipose tissue, skeletal muscle
GLUT_ receptors are found in beta cells and GLUT_ receptors in muscle and fat.: 2, 4
Inhibits glucagon release by what cells?: Alpha cells of pancreas
True/False: Serum C-peptide is present with exogenous insulin uptake.: FALSE
Insulin vs. Glucagon: p. 162
Glucagon _______ stuff, turns glycogen synthase _____, turns phosphorylase ___.: Phosphorylates, OFF, ON
Insulin _______ stuff, turns glycogen synthase _____, turns phosphorylase ___.: Dephosphorylates, ON, OFF
Cholesterol synthesis: p. 162
Rate limiting step is catalyzed by what enzyme?: HMG-CoA reductase
Lovastatin (inhibits/catalyzes) HMG-CoA reductase.: Inhibits
2/3 of plasma cholesterol is esterified by _____________.: Lecithin-cholesterol acyltransferase (LCAT)
Major apolipoproteins: p. 162
A-I does what?: Activates LCAT
B-100 binds to _______ receptor.: LDL
C-II is a cofactor for what enzyme?: Lipoprotein lipase
E does what?: Mediates extra (remnant) uptake

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