omranalzobaidi's version from 2015-12-08 23:16

Other People's Awesome Stuff

Biochemistry (by snopearl69)

Rate-determining enzymes of metabolic processes

Question Answer
GlycolysisPhosphofructokinase-1 (PFK-1)
TCA cycleIsocitrate dehydrogenase
Glycogen synthesisGlycogen synthase
GlycogenolysisGlycogen phosphorylase
HMP shuntGlucose-6-phosphate dehydrogenase (G6PD)
De novo pyrimidine synthesisCarbamoyl phosphate synthetase II
De novo purine synthesis Glutamine-PRPP amidotransferase
Urea cycleCarbamoyl phosphate synthetase I
Fatty acid synthesisAcetyl-CoA carboxylase
Fatty acid oxidationCarnitine acyltransferase I
KetogenesisHMG-CoA synthase
Cholesterol synthesisHMG-CoA reductase

Citric acid cycle

Item Next
Isocitrate#Alpha-ketoglutarate #
Alpha-ketoglutarate #Succinyl Co-A
Succinyl Co-ASuccinate

Amino Acids

Question Answer
Glucogenic essential amino acidsMet, Val, Arg, His
Glucogenic/ketogenic essential amino acidsIle, Phe, Thr, Trp
Ketogenic essential amino acidsLeu, Lys


Question Answer
AcidicAsp and Glu
BasicArg, Lys, His (no charge at body pH)


Amino acid derivatives
Question Answer
PhenylalanineTyrosine (thyroxine) --hydroxylase--> Dopa (melanin) --decarboxylase--> Dopamine --beta hydroxylase--> NE --SAM , PNMT ( cortisol )> Epi
TryptophanNiacin (cofactor B6) (NAD+/NADPH) --> Serotonin (cofactor BH4) (melatonin)
HistidineHistamine (cofactor B6)
GlycinePorphyrin (cofactor B6) --> Heme
ArginineCreatine, urea, NO (BH4)
GlutamateGABA (cofactor B6), Glutathione

Urea Cycle

Ordinarily, Careless Crappers Are Also Frivolous About Urination
Item Next
Ornithine ( + carbamoyl phosphate, ornithine transcarbamoylase)Citrulline ( + Aspartate, argininosuccinate synthetase)
Citrulline ( + Aspartate, argininosuccinate synthetase)Argininosuccinate (Argininosuccinase)
Argininosuccinate (Argininosuccinase)Arginine ( - fumarate, arginase)
Arginine ( - fumarate, arginase)last
Urea and Ornithine

Vitamin Deficiencies

VitaminFunctionDeficiencyExcessCauses of deficiency
Vitamin AAntioxidant, Visual pigments, normal differentiation of epithelial cells into specialized tissue. Found in liver and leafy vegetablesNight blindness, dry skinArthalgias, fatigue, headaches, skin changes, sore throat, alopeciaFat malabsorption
Vitamin B1 (Thiamine)in thiamine pyrophosphate (TPP). Important for: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase (HMP shunt), branched-chain AA dehydrogenaseATP depletion --> Wernicke Koraskoff Syndrome, Beri-Beri (polyneuritis, symmetric muscle wasting; dilated cardiomyopathy in wet beri beri)None (B1)Alcoholism/malnutrition, malabsorption
Vitamin B2 (Riboflavin)Cofactor in redox rxns (FAD, FADH2, FMN, etc)Cheilosis (inflammation of the lips, scaling and fissures at corners of mouth), corneal vascularizationNone (B2)N/A (B2)
Vitamin B3 (Niacin)Constituent of NAD+ and NADP+. Derived from tryptophan. Requires B6 for synthesisGlossitis. Severe deficiency leads to pellagra -- diarrhea, dermatitis, dementia (seen in Hartnup disease, carcinoid syndrome, and INH)Facial flushingExcess untreated corn
Vitamin B5 (Pantothenate)Essential component of CoA and fatty acid synthaseDermatitis, enteritis, alopecia, adrenal insufficiencyNone (B5)N/A (B5)
Vitamin B6 (Pyridoxine)Converted to pyridoxal phosphate, used in transamination, decarboxylation, glyocogen phosphorylase , cystathionine synthesis, and heme synthesis. Required to make niacin from tryptophan.Convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemiasNone (B6)INH, OCPs
Vitamin B12 (Cobalamin)Cofactor for homocysteine methyltransferase and methylmalonyl-CoA mutaseMacrocytic, megaloblastic anemia, hypersegmented PMNs, neurologic symptomsNone (B12)Malabsorption (sprue, enteritis), Diphyllobothrium latum, pernicious anemia, gastric bypass, Crohn's disease
Folic acidConverted to THF, required for 1-carbon transfer/metyl rxns and synthesis of nitrogenous bases in DNA/RNAMacrocytic, megaloblastic anemia, no neurologic symptomsNone (Folate)Alcoholism, drugs (phenytoin, sulfonamids, MTX), can be seen in pregnancy
BiotinCofactor for carboxylation rxns (pyruvate carboxylase, Acetyl-CoA carbocylase, Propionyl-CoA carboxylase)Dermatitis, alopecia, enteritisNone (Biotin)Antibiotic use or excessive ingestion of raw eggs
Vitamin C (Ascorbic acid)Antioxidant, facilitates Fe absorption, Hydroxylation of proline and lysine in collagen synth., dopamin beta-hydroxylase (Dopamine --> NE)Scurvy (swollen gums, bruising, anemia, poor wound healing)Not enough fruits and vegetables
Vitamin DIntestinal absorption of calcium and phosphate, bone resorptionrickets, osteomalacia, hypocalcemic tetanyhypercalcemia, hypercalciuria, appetite loss, stupor (seen in sarcoidosis, b/c of activation by epitheloid macrophages)Not enough sunlight, not drinking milk
Vitamin EAntioxidant (protects erythrocytes and membranes from free-radical damage)hemolytic anemia, muscle weakness, neurodysfunctionNone (E)N/A (E)
Vitamin KCatalyzes gamma-carboxylation of glutamic acid residuesNeonatal hemorrhage with increased PT and PTT. Poor coagulationNone (K)Prolonged antibiotic use. Prematurity.
ZincEssential in 100+ enzymesDelayed wound healing, hypogonadism, decreased adult hair, dysgeusia (distorted taste), anosmia, predisposition to alcoholic cirrhosisNone (zinc)N/A (zinc)

Immunohistochemical stains

StainCell type
VimentinConnective tissue
CytokeratinEpithelial cells

Cofactor uses

B6Glycogen phosphorylase
B6Cystathionine synthesis
B6Heme synthesis
B6Niacin synthesis
B1Pyruvate dehydrogenase
B1alpha-ketoglutarate dehydrogenase
B1Branched-chain AA dehydrogenase
B5Fatty acid synthase
Folic acid1-carbon transfer/methylation
SAMTransfer of methyl units
SAMConversion of NE to epinephrine
BiotinPyruvate dehydrogenase
BiotinAcetyl-CoA dehydrogenase
BiotinProprionyl-CoA dehydrogenase
Vitamin CDopamine beta-hydroxylase (dopamine to NE)

Metabolism sites

Fatty acid oxidation/Beta oxidationMitochondria
Acetyl-CoA productionMitochondria
TCA cycleMitochondria
Oxidative phosphorylationMitochondria
Fatty acid synthesisCytoplasm
HMP shuntCytoplasm
Protein synthesisCytoplasm
Steroid synthesisCytoplasm
Heme synthesisBoth
Urea cycleBoth

Oxidative phosphorylation poisons

PoisonWhat it does
RotenoneDirectly inhibits electron transport --> decreased protein gradient
CN-Directly inhibits electron transport --> decreased protein gradient
AntimycinDirectly inhibits electron transport --> decreased protein gradient
CODirectly inhibits electron transport --> decreased protein gradient
OligomycinDirectly inhibits mitochondrial ATPase --> electron transport stops
2,4-DNPuncouples ATP synthesis and electron transport (which continues)
Aspirinuncouples ATP synthesis and electron transport (which continues)
Thermogeninuncouples ATP synthesis and electron transport (which continues)

Tyrosine/Dopamine/NE/Epi pathway

Tyrosine --> L-DopaTyrosine hydroxylase
L-Dopa --> DopamineDopamine decarboxylase
Dopamine --> NEDopamine Beta hydroxylase
NE --> EpiPhenylethanolamine-N-methyltransferase (SAM dependent)