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142 Cards in this Set
- Front
- Back
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4 levels of structure in proteins
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primary
secondary tertiary quaternary |
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The primary structure is a sequence of
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unique, precisely defined amino acid sequence
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amino acid sequence is important for which several reasons?
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1) essential to to elucidating it mechanism of action
2) determines the 3-D structure of protein 3) sequence determination is a component of molecular pathology |
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Two primary structure diseases
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Sickle Cell Anemia
Cancer |
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Causes of sickle cell anemia and cancer
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mutation of an amino acid that destroys the sequence of an amino acid chain. Sickle cell-mutation of Glu6 to Val
Cancer-Gly12 to Val |
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Four major protein secondary structures?
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Alpha helix
Beta sheet Turn Coil |
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How many amino acids per turn in an alpha helix polypeptide cahin
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3.6
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In alpha helix structure where does the hydrogen bonding occur?
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between the carboxy group and the amino hydrogen 4 amino acids along the chain
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What direction of rotation are L amino acids found?
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counterclockwise (right handed)
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What two amino acids are not present in the alpha helix structure?
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Proline and glycine
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Why can't proline be found in the alpha helix structure?
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It has an imino group. that group produces destablizing bending and interferes with they H bonding
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Why can't glycine be found in the alpha helix structure?
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It is much more flexible because it lack the R group.
It introduces a weakness in the cylindrical feature. |
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Turns and coils often contain which two amino acids?
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Proline
Glycine |
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Turns will always be found going in what direction
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antiparallel
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Coils will always having which direction?
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parallel
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Silky, stretchy proteins are
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alpha helix
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Filmy like proteins are
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beta sheet
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Turns and coils often contain which two amino acids?
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Proline
Glycine |
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Turns may be found in the
(function) |
catalytic centre of an enzyme
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coils function
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add flexiblity to the protein and allows for conformational changes
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Turns will always be found going in what direction
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antiparallel
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Coils will always having which direction?
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parallel
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Silky, stretchy proteins are
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alpha helix
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Filmy like proteins are
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beta sheet
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Turns may be found in the
(function) |
catalytic centre of an enzyme
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coils function
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add flexiblity to the protein and allows for conformational changes
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Hydrogen bonding in Beta sheets occure if
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several strands lay next to each other
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A normal brain prion consists of mostly
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alpha helices and random coil
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A model of disease causing prion has
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extensive beta sheet structure
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Diseased prions are more:
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stiff, tends to aggregate, and has limited resistance to digestion by proteases
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How do prion diseases propogate?
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diseased prions promote refolding of normal prions into the diseased form
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Example of prion diseases
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Alzheimers (humans)
Scrapie (sheep) Bovine Spongiform Encephalopathy (mad cow) Chronic Wasting Disease (elk/deer) |
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4 components of amino acid
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carbon centered
carboxyllic group amino group side chain |
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What amino acid's R chain is a Hydrogen
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glycine
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Amino acids link together to form?
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peptide
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The amino group is what charge.
at low pH and high concentration of H+ |
positve ion (basic)
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the carboxyllic group is what charge.
at high pH and low concentration of H+ |
negative (acidic)
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All 20 Amino Acids are chiral except
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Glycine
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CORN
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L-amino acid
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All amino acids are what form
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L-form
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What peptide antibiotics contain D amino acids?
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gramicidin (neosporin component)
Actinomycin D |
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Why are peptide anitbiotics useful in humans?
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They contain D amino acids and the body isnt used to breaking them down, so they have more longevity in the body.
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what amino acids are non-polar
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Glycine
alanine Valine Leucine Methionine Isoleucine Proline |
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What amino acids are Aromatic?
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Phenylalanine
Tyrosine Tryptophan |
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what amino acids are polar?
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Serine
Cysteine Threonine Asparagine Glutamine |
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what amino acids are Postiviely charged
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Lysine
Histidine Arginine |
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what amino acids are negatively charged?
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Aspartic acid
Glutamic acid |
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What two amino acids contain sulfur inside their chain?
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methionine
cysteine |
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Which amino acid is cyclic?
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Proline
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Which amino acids have a side chain that allows it to be ionized?
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Tyrosine
Cysteine |
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What are important characteristics of charged amino acids?
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Hydrophillic surfaces in proteins
salt bridges in proteins acid/base and covalent protein chemisty |
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The direction of the peptide bond is ____ terminal to ___ terminal
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N-terminal to C-terminal
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A protein is least soluble when the ___ = the ___
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pH = proteins pI
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Basic amino acids (positive charged) will be postively charged when
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pH is < pKa value
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Acidic amino acids (negative charge) will be negatively charged when
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pH is > pKa value
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What three ways are free amino acids used in the body?
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protein and peptide synthesis
Essential Nitrogen-containing compounds Energy Production |
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Amino acids that are converted to glucose or glycogen are called?
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glucogenic amino acids
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The glucogenic amino acids are:
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Alanine
arginine asparagine cysteine glutamine glycine histidine hydroxyproline methionine proline serine valine |
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Amino acdis that give rise to Ketone bodies are called?
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Ketogenic amino acids
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The ketogenic amino acids are:
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leucine
lysine |
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Amino acids that are both keotgenic and glucogenic are:
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threonine
isoluecine phenylalanine tyrosine tryptophan |
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Amino acids are used in energy production only under what condition
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when we are starving
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what are the essential amino acids?
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isoleucine
leucine lysine methionine phenylalanine threonine tryptophan valin |
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What are the semi essential amino acids
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histidine
arginine |
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What are the non essential amino acids?
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Asparagine
Glutamine Aspartate Glutamate Glycine Alanine Proline Tyrosine Cysteine Serine |
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Tyrosine is biosynthesized from what?
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Phenylalanine
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Cysteine is biosynthesized from what?
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Methionine
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What is the recommended daily allowance of protein for an individual?
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.8 g "high quality" protein per kg of weight
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What type of diets have been used to discourage herpes breakouts?
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High in Lysine low in arginine
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What are the precursors for epinephrine?
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Dopamine
Tyrosine (adrenaline hormone) |
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what are the essential amino acids?
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isoleucine
leucine lysine methionine phenylalanine threonine tryptophan valin |
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what is the precursor for dopamine?
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Tyrosine
(neurotransmitter) |
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What are the semi essential amino acids
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histidine
arginine |
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what is the precursor for Thyroxine?
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Tyrosine
(thryoid hormone) |
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What are the non essential amino acids?
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Asparagine
Glutamine Aspartate Glutamate Glycine Alanine Proline Tyrosine Cysteine Serine |
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Tyrosine is biosynthesized from what?
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Phenylalanine
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Cysteine is biosynthesized from what?
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Methionine
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What is the recommended daily allowance of protein for an individual?
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.8 g "high quality" protein per kg of weight
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What type of diets have been used to discourage herpes breakouts?
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High in Lysine low in arginine
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What are the precursors for epinephrine?
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Dopamine
Tyrosine (adrenaline hormone) |
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what is the precursor for dopamine?
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Tyrosine
(neurotransmitter) |
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what is the precursor for Thyroxine?
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Tyrosine
(thryoid hormone) |
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What are the precursors for Melatonin?
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Serotonin
Tryptophan (neurohormone) |
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what are the precursors for Niacin?
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Tryptophan
(vitamin B3) |
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Whare is the precursor for Seratonin or 5HT?
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Tryptophan
(neurotransmitter) |
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What is the precursor for GABA?
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Glutamate acid
(neurotransmitter) |
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What is the precursor for Histamine?
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Histidine
(allergy and stomach acid production) |
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where is Glycine found?
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Its a CNS neurotransmitter found in the spinal fluid
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What are Hydroxylysine and Hydroxyproline important for?
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mainting collagen structure
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what is carnitine used for?
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Lys derivative
fatty acid transport |
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what is creatine use for?
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It is converted into creatine phosphate and stored in the muscles, where it is used for energy
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what is Taurine used for?
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critical for bile acid synthesis and osmoregulation
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what is Homocysteine?
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associated with heart problems
(artheroslerosis, heart attacks, strokes, blood clot formation, alzheimers disease) |
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What are the precursors of aspartane?
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aspartic acid
phenyl alanine |
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what is aspartane used for?
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diet soda
sweeteners |
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what are the precursors for monosodium glutamate?
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Glutamic acid
Sodium hydroxide |
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What is MSG?
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used in chinese food
makes it taste better |
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What 3 amino acids are phosphorylated?
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Serine
Threonine Tyrosine |
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phenylketonuria occurs because of the the buildup of what amino acid?
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phenylalanine
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Phenylketonuria results from what
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lack of enzyme to convert phenylalanine to tyrosine
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Maple syrup disease is caused by lack of enzyme to metabolize which amino acids?
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leucine
isoleucine valine |
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What can be done to help children with maple syrup disease?
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Vitamin B (thiamine) injections
dialysis special artificial diet low in leucine, isoleucine, and valine |
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What is the synthetic form of Oxytocin?
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Pitocin
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what does pitocin do?
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induces labor
builds trust and bonds stimulates milk release |
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What does vasopressin do?
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stimulates re-asorption of water in the kidney
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Patients with what disease are deficient in vasopressin?
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diabetes insipidus
they excrete large volumes of water |
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PRIALT contains
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ziconotide
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what is ziconotide
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25 amino acid peptide
a non narcotic pain reliever it must be administered intrathecally |
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What two barriers are there to peptide drugs?
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Oral-digestive system designed to breakdown polypeptides into amino acids
Intestinal absorptive epithelium-most drugs are hypophillic so they cant pass the phosolipid bilayer |
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Peptide drug pros
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High activity
High specificity little nonspecific binding minimum other drug interaction less accumulation in tissue less toxicity less potent biological and chemical diversity |
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Peptide drug cons
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low oral bioavailability
injection required less stable difficult delievery and transportation through memrane costly less soluble immunological risk cleared form body quickly |
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What is an amino acid with both a postive and negative charge?
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Zwitterion
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All amino acids are chiral except which one?
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glycine
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What are Globular Proteins?
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Tertiary structures that are:
compact highly-folded proteins that are water soluble |
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What are Fibrous proteins?
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Tertiary structures that are:
stiff elongated proteins that tend to form insoluable fibers |
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Myoglobin
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globular
Made to work with the other biological fluids They are soluble surfaces are hydrophillic insides are hydrophobic ex.. insulin, hemoglobin, antibodies |
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Collagen
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Fibrous
hair skin wool nails is insoluble |
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What protein structure has multiple polypeptides
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Quaternary
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What is required to maintain collagen's quaternary structure?
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lysyl hydroxylase
prolyl hydroxylase |
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What is vitamin C used for?
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it is a cofactor for hydroxylation to maintain collagen's structure
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Prolonged Vitamin C defiencey leads to what disease?
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Scurvy
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What is the complete or partial unfolding of a protein?
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Denaturation
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How can proteins be denatured?
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Heat-molecular motion
Mechanical agitation-molecular motion pH-ion and H-bond disruption Detergents-hydrophobic disruption Organic Solvents (acetone, alcohols, etc)-hydrophobic disruption Chaotropic Agents (chaos causing)- 5-10 M urea or guanidinium ion appear to cause hydrophobic disruption |
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How can some proteins be renatured?
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remove the denaturant
although most denaturation is irreversible |
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Where is Myoglobin found? and what is it used for?
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Found in muscle cells
For O2 storage single polypeptide |
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Where is Hemoglobin found? and what is it used for?
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Found in red blood cells
For O2 transport to tissue multi polypeptide |
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What cofactor does myglobin and hemoglobin need?
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Heme
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Heme is what type of Cofactor?
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Prosthetic group
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What is the polypeptide part of a conjugated protein?
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Apoprotein
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What is the complete biologically active protein conjugate?
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Holoprotein
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What is the Normal Hematocrit Range?
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Female: 38-46%
Male: 42-53% |
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What is Anemia?
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Deficiency of functional RBC's and or hemoglobin
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What type of compound is Heme?
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Aromatic
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When Oxygen is coordinated to Iron, blood is what color?
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Red
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When Oxygen is not coordinated to iron, blood is what color?
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Blue
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What is used to overcome Carbon Monoxide Poisoning?
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Exposure to O2 rapidly
Hyperbaric Chamber |
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Why do we get Carbon Monoxide poisoning?
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CO has an affinity (it binds to) heme more than O2 binds to heme..so it gets in our blood stream.
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Allosteric Activators?
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compounds that bind at sites other than the active catalytic site and regualte the enzyme activity through conformational changes affecting the catalytic site
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Hemoglobin exhibits?
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allostery
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What happens when O2 binds the heme iron to each protein?
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hemoglobin undergoes conformational changes.
The hemoglobin binds the O2 more tightly |
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What is cooperative binding?
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When first binding of O2 makes conformational changes to other subunits and allows binding for those subunits to be easier.
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What are allosteric activators?
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compounds bind at sites other than the active catalyitc site and regulate the enzyme through conformational changes
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