Biochemistry Flashcards
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Protein involved in the first step of heme synthesis. Conjugates to bile acids, drugs, and other metabolites. Major inhibitory neurotransmitter in the spinal cord. Non-polar amino acid with the smallest side chain.
Glycine
Protein involved in transporting ammonia and pyruvate carbons from skeletal muscle to liver. Together with glycine, constitutes a major fraction of free amino acids in the blood.
Alanine
Accumulates in PKU, precursor of Tyrosine
Phenylalanine
Largest side chain. Precursor for niacin, serotonin, melatonin.
Tryptophan
Transfers methyl groups (SAM), and precursor of homocysteine
Methionine
Imino acid, interrupting alpha-helix structure of globular proteins. Contributes to the fibrous structure of collagen.
Proline
Branched chain amino acids that accumulate in MSUD
Valine, Isoleucine, Leucine
Contains polar hydroxyl group. O-linked glycosylation and phosphorylation of proteins.
Serine, Threonine, Tyrosine
Precursor of L-Dopamine, Dopamine, Norepinephrine, Epinephrine, Melanin, Thyroxine
Tyrosine
Contains carbonyl group and an amide group that can form hydrogen bonds
Glutamine, Asparagine
Site for N-linked glycosylation of proteins
Asparagine
Deaminated by glutaminase to form ammonia which carries nitrogen from peripheral tissues to the liver
Glutamine
Contains a sulfhydryl group. Participates in the biosynthesis of Coenzyme A (CoA). Two of which can combine by a covalent disulfide bond producing a protein complex found in keratin.
Cysteine
Acidic amino acids. Containing carboxylate group. Participate in ionic interactions, and serve as proton donors.
Aspartate, Glutamate
Precursor for GABA and glutathione
Glutamate
Basic amino acids, proton acceptors.
Histidine, Arginine, Lysine
At neutral pH, these basic amino acids are positively charged.
Arginine and Lysine
Basic amino acid with no charge
Histidine
Precursor of Histamine, released at the Hypothalamus via circadian rhythm
Histidine
Precursor of creatinine, urea, and nitric oxide
Arginine
21st amino acid where a selenium atom replaces the sulfur of the structural analog. Inserted into polypeptides during translation but is not specified by a simple 3-letter codon
Selenocysteine
Plant L-alpha-amino acid present in Lathyrus seeds, implicated in neurolathyrism (progressive, irreversible, spastic paralysis of lower extremities)
Homoarginine and B-N-Oxalyldiaminopriopionic acid (B-ODAP)
Plant L-amino acid, neurotoxic found in Cycad seeds. Implicated in Amyotropic Lateral Sclerosis in natives of Guam
*BONUS: other name for ALS
B-methylaminoalanine
BONUS: Lou-Gherig’s disease
All amino acids are chiral except for?
Glycine
Protein configuration
L-configuration
Bacterial Cell Wall protein configuration
D-configurations
An amino acid with no net charge
Zwitterion
Essential Amino Acids
Phenylalanine Valine Tryptophan Threonine Isoleucine Methionine Histidine Arginine Lysine Leucine
Nutritionally SEMIessential amino acid
Arginine
Amino acids synthesized in the body but only from precursors
Cystine, Tyrosine
Protein structure determined by SEQUENCE.
Primary structure
Partial double-bond character, rigid and planar, generally in TRANS configuration. Disrupted by hydrolysis through prolonged exposure to a strong acid/base at elevated temperature
Peptide Bonds
Stepwise process of identifying the specific amino acid at each position in the peptide chain
Sequencing
1-fluoro-2,4-dinitrobenzene
Sanger’s Reagent
Phenylisothiocyanate
Edman’s Reagent
Folding of short 3-30 residue contiguous segments of polypeptide into geometrically-ordered units, stabilized by hydrogen bonding
Secondary structure
Spiral structure with polypeptide backbone core with side chains extending outward, 3.6 AA per turn, disrupted by proline, or AAs with large/charged groups
Alpha helix
Supersecondary structures produced by packing side chains from adjacent secondary structural elements close to each other
Motifs
Specialized group of proteins required for the proper folding of many species of proteins. Prevents aggregation.
Chaperones
Results in the unfolding and disorganization of the protein’s secondary and tertiary structures. NOT accompanied by the hydrolysis of peptide bonds.
Denaturation
Fatal, neurodegenerative diseases characterized by spngiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insiluble protein aggregates in neural cells.
Prion Diseases
Enzyme involved in the rate-limiting step of converting Acetyl CoA to Malonyl CoA in Lipogenesis
Acetyl CoA carboxylase
Sequence of steps in elongation of lipids, repeated seven times
Condensation, Reduction, Dehydration, Reduction
Where do fatty acids undergo further elongation?
Endoplasmic Reticulum
Up to which “carbon” can desaturation of fatty acids occur in the Endoplasmic Reticulum?
Carbon 9
Apart from producing NADH for fatty acid synthesis, where can you find the enzyme isocitrate dehydrogenase?
Conversion of isocitrate to alpha-ketoglutarate in the TCA cycle
What coenzyme does carboxylase use?
Biotin
How are TAGs synthesized?
Addition of 2 fatty acyl CoA to glycerol-3-phosphate
Removal of phosphate
Addition of 3rd fatty acyl CoA
Kaya TRIacylglycerol
In Beta Oxidation of Lipids/Fatty Acids, what is the rate-limiting step?
Translocation of fatty acyl CoA from the cytosol to the mitochondria
Enzyme used in translocation of fatty acyl CoA from the cytosol to the mitochondria
Carnitine-palmitoyl transferase
What are the products of Beta-Oxidation? (Acetyl CoA, NADH, FADH)
8 Acetyl Coa, 7 NADH, 7 FADH
Where does Beta-Oxidation of Fatty Acids occur?
Mitochondria
Where does carnitine acyltransferase-1 attach fatty acyl to carnitine?
Outer mitochondrial membrane
Where does carnitine acyltransferase-2 attach fatty acyl to acyl CoA?
Mitochondrial matrix
Degradation of Fatty Acyl CoA steps repeated 7 times
Oxidation, Hydration, Oxidation, Thiolysis
Products of the degradation of Fatty Acyl CoA
FADH2, NADH, Acetyl CoA
Why can’t the liver use ketones as fuel?
Because it lacks succinyl CoA acetoacetate-CoA transferase (thiophorase)
Main Apoprotein mediating the secretion of VLDL
Apo-B 100
Main apoprotein mediating the secretion of chylomicrons
Apo B-48
Apoprotein cofactor of lipoprotein lipase
Apo C-II
Apoprotein mediating uptake of chylomicron remnants and IDLs
Apo-E
Hyperlipoproteinemia causing thrombosis due to inhibition of fibrinolysis
Familial Lipoprotein (a) Excess
Hyperlipoproteinemia not associated with increased risk of coronary disease
Type I Familial Lipoprotein Lipase Deficiency
Hyperlipoproteinemia beneficial to health and longevity
Familial hyperalpha-lipoproteinemia (High HDL)
Hypolipoproteinemia caused by a defect in the loading of Apo-B with lipid (no chylomicrons or VLDL).
BONUS: How do you treat this?
Abetalipoproteinemia.
Treated with large doses of fat-soluble vitamins, particularly Vitamin E
Hypoprotenemia causing Tangier Disease, Fish-eye disease, and Apo-A1 Deficiency
Familial-alpha lipoprotein deficiency
