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165 Cards in this Set
- Front
- Back
- 3rd side (hint)
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which aa's have 4 enantiomers?
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isoleucine
threonine |
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which aa is the simplest aa known?
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glycine
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how do aa's exist at pH 7.4?
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dipolar zwitter ions
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which aa is the hydroxylated form of alanine?
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serine
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where are hydrophilic aa's found?
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on the surface of proteins
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which aa is found in the bends of folded polypeptide chains?
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proline
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is arginine an aa that is hydrophobic or hydrophilic?
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hydrophilic
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which of the aa's has branched side chains?
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leucine
isoleucine valine |
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which are the aromatic aa's?
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phenylalanine, tyrosine, tryptophan
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what is the most abundant protein in the mammalian organism?
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collagen
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vitamin C is required in the formation of which aa?
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hydroxyproline
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which modified aa is a constituent of elastin?
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isodesmosine
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which modified aa is associated with blood coagulation?
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gamma-carboxyglutamate
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which aa is used in the hepatic conjugation of bile acide?
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taurine
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name an inhibitory NT in the brain
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gamma-aminobutyrate and glycine
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is alanine an essential aa in young cats?
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no
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which aa's are essential in cats?
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methionine
phenylalanine taurine arginine |
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which aa's are routinely oxidized in muscle tissue?
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branched chain aa's:
leucine isoleucine valine |
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do benzodiazepines (valium) act by blocking the action of GABA at post-synaptic receptor sites?
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no
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is the formation of highly organized amyloid aggregates a generic property of polypeptides?
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yes, it may be
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what directly influences the secondary, tertiary, and quaternary structure of proteins?
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primary structure
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how is the secondary structure of aa's held together?
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H-bonds between carboxyl and amino groups of the peptide bond
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are disulfide bonds part of the secondary structure of all mammalian proteins?
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no
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what is the tertiary structure of a protein?
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the overall 3D arrangement of its polypeptide chain
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how are alpha helixes stabilized?
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H-bonding between amide H's and carbonyl O's of different peptide bonds
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how are the beta pleated sheets stabilized?
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H-bonding between separate chains that run either parallel or antiparallel to one another
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What do chaperones do?
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guide polypeptide chains to their tertiary structure while the primary sequence is being formed
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what level of organization does protein denaturation affect?
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affect all levels of protein structure
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what do globular proteins look like
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spherical and hydrophilic
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what is joined in a peptide bond?
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alpha carboxyl group of one aa and the alpha amino group of another aa
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how many aa residues are there in the active form of insulin?
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51
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what are coenzymes?
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small, organic, non-protein molecules that carry chemical groups between enzymes
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what do phosphatases do?
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remove phosphate groups from phosphorylated compounds
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which enzyme is activated irreversibly?
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pepsinogen
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what is the characteristic enzymatic activity in the digestive lumen?
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hydrolysis
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how many different types of enzymes are normally present in a mammalian cell?
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2000
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what do hydrolases catalyze?
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the cleavage of bonds between carbon and some other atom by the addition of water across the bond
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what hormone acts by increasing enzyme synthesis in its target cells?
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cortisol
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what is urease?
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an enzyme found in microbes of the rumen
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what do synthases do?
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stimulate synthesis without using ATP
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which suffix refers to an enzuyme?
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-ase
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which is the variable that measures the affinity of an enxyme for its substrate?
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Km (read K sub m)
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what are temperature and pH known to affect?
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Km and Vmax
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what happens to the maximal velocity of an enzyme-catalyzed reaction in the presence of an irreversible inhibitor?
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decreased in the presence of an irreversible inhibitor
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which tissue type has the highest concentration of MB dimer for creatine phosphokinase?
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heart
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which therapeutic inhibitor is considered to be a suicide substrate?
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aspirin
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what is the y-intercept on a Lineweaver-Burk plot?
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1/Vmax
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what is the Mechaelis-Menten equation?
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V=Vmax[S]/(Km+[S])
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what are competitive inhibitors and what do they do?
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structural analogues of the substrate; Vmax remains unchanged; can be used as therapeutics to control the activity of target enzymes; effects can be reversed by increasing the substrate concentration
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which type of enzyme inhibitor is known to affect both Vmax and Km?
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uncompetitive
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which aa is needed for hepatic tyrosine biosynthesis?
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phenylalanine
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which aa is needed for cysteine formation
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methionine
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which aa is needed for serotonin and melatonin formation?
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tryptophan
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which amino acids are considered "essential" in adults?
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leucine
isoleucine valine taurine (cats) threonine lysine phenylalanine tryptophan methionine |
li(v)ttlptm
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which amino acids are considered "essential" in young animals?
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histidine
arginine glycine (chickens) |
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how do G-proteins work as control proteins?
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the combination of G-prots with GTP activates them,
then adenylate cyclase is either activated or inhibited, intracellular cAMP concentration changes .................... calmodulin is activated after binding with 4 molecules of Ca++, the activated protein then binds with intracellular enzymes and modifies their activities |
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what are 2 example of irreversible proteolytic enzymes found in the pancreas?
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exopeptidases
endopeptidases |
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what is ALKALINE PHOSPHATASE?
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enzyme that removes PO4 groups,
most active at alkaline pH |
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what are the most imporatant ALP serum sources?
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liver (L-ALP) bile duct cells
bone (B-ALP) osteoblasts leukocytes dog liver (C-ALP) |
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what does an elevated ALP indicate?
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L-ALP: bile duct damage
B-ALP: bone growth/fractures Leuk-ALP: increase in all blood cell types, cancer |
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what does ASPARTATE AMINOTRANSFERASE do?
(AST) |
transfers an amino group from aspartate->glutamate
oxaloacetate->a-ketogluterate |
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what are the primary sources for AST?
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liver
skeletal/cardiac muscle |
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what does ALANINE AMINOTRANSFERASE do?
(ALT) |
transfers an amino group from alanine->glutamate
pyruvate->a-ketogluterate |
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what are the primary sources for ALT?
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liver
skeletal/cardiac muscle |
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what are the tetramer combinations of LACTATE DEHYDROGENASE?
(LDH) |
HHHH
HHHL HHLL LLLL LLLL |
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what does LDH do?
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involved with conversion of pyrvate to lactate and vice versa along with the conversion of NADH to NAD+
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what can LDH tell you?
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if a cardiac event has taken place
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what does GAMMA GLUTAMYL TRANSFERASE do?
(GGT) |
involved in transport of aa's into cells
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where is GGT found?
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biliary epithelial cells
pancreas renal tubular cells mammary glands (some species) |
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what does elevated serum GGT indicate?
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choleostasis, escessive bile back-up (esp in horses)
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what does high urine GGT indicate?
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injury to renal epithelial cells
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what is the function of CREATINE KINASE?
(CK) |
energy vault
creatine phosphate + ADP <-> creatine + ATP CK1-brain (CSF) CK2-cardiac musc CK4-skeletal muscle CK4-mitochondria |
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what does an elevated serum CK3 indicate?
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injury to skeletal muscle, muscular dystrophy, myopathy, rhabdomyolysis
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what does SORBITOL DEHYDROGENASE do?
(SDH) |
sorbitol + NAD+ <-> fructose + NADH
it is a cytoplasmic protein |
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what does an elevated SDH indicate?
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liver damage
-especially helpful in LA where ALT is not informative |
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what do AMYLASES do?
(AMS) |
break down starches into smaller polysaccharides
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what are the primary sources of AMS?
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pancreas
liver salivary glands (not in Ar or Ca) |
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what does elevated AMS indicate?
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pancreatic disease
pancreatitis check LPS and TLE |
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what does LIPASE do?
(LPS) |
break down triglycerides into FAs
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what is the primary source of LPS?
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pancreas
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what does elevated LPS indicate?
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pancreatic disease
check AMS and TLE |
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what does an elevated TRYPSIN-LIKE ENZYME indicate?
(TLE) |
pancreatic disease
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what is the primary source of TLE?
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pancreas
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how is TLE measured?
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RIA
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what does ALCOHOL DEHYDROGENASE do?
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first step in the metabolism of ethanol
deficient in some asian people |
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what are the consequences of ethylene glycol ingestion?
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crystals, cause physical damage, can rupture mito and cells
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what are the stages of ethylene glycol toxicity?
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1-CNS
2-Cardio 3-renal treat with EtOH or fomepizole |
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what do insecticides target?
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AChE
-insecticides usually OP's or carbamates |
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what are the signs of OP/carbamate poisioning
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salivation, lacrimation, urination, defecation, dyspnea, bradycardia, mitosis, fasiculations, tremors, weakness, flacid paralysis, restlessness, hyperactivity, seizures
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how can you diagnose OP/carbamate poisioning with tests?
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AChE assay
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how does penicillin work?
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inhibits the synthesis of bacterial cell wall peptidoglycan by inhibiting glycopeptide transpeptidase by binding its active site irreversibly
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how do you administer penicillin?
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IM, it is unstable in the stomach
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how does fosfomycin work?
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inhibits synthesis of TB cell wall peptidoglycan by inhibiting the MurA enzyme
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what do beta-lactamase inhibitors do?
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give new life to old antibiotics
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what is etoposide?
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a chemotherapy drug that inhibits DNA repair enzymes and therefore increases p53 enzymes
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what is an ACE inhibitor?
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something that blocks the conversion of ATI to ATII
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what do cholesterol statins do?
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inhibit key conversion enzymes in conversion
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what enzyme does glutothione peroxidase require?
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needs selenium
uses glutathione to eliminate H2O2 |
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what is the consequence of Se or Vit E deficiency?
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build-up of lipid peroxidases, which in turn causes skel and cardiac musc damage...white fat accumulates in muscles- stiffness, flaccid muscles
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what are some of the enzymes that require Cu as a cofactor?
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superoxidase dismutase
cytochrome C oxidase lysine amino oxidase tyrosinase |
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what are the symptoms of Vit A deficiency?
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vision
skin- keratin epithelium of resp, repro, dig, tracts- BIRDS |
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what vitamin is required by cats?
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Vitamin A, they can't convert betacarotine to retinol, eat liver
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what is the result of a lysosomal storage disease?
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accumulation of substrates in lysosomes, leading to physical intracellular crowding
-neurologic consequences, pressure on spinal cord |
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what is Gaucher?
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lsd
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what is Fabry?
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lsd
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what is Tay-Sachs?
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lsd
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what is Niemann-Pick?
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lsd, caused by deficiency of the enzyme acid sphingomyelinase
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what are the symptoms of a lysosomal storage disease?
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dysmorphic features
psychomotor regression ocular abnormalities hepatosplenomegaly |
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are there some lysosomal storage diseases that are genetic and only effect certain species and breeds?
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yes:
ceroid lipofuscinosis-dog, cat fucosidosis-springer spaniel flucocerebrosidosis (Gauchers)- australian silky spaniel GM1 gangliosidosis-dog, cat, ovine GM2 gangliosidosis (Tay-Sachs B)-german shorthaired pointer mucopolysacchiridosis I- dogs, cats, mice |
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what is alpha mannosidosis?
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an acquired lysosomal storage disease that leads to neuro problems in horses, sheep cattle
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what can cause acquired lysosomal storage disease?
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locoweed
poison peas sida carpinifolia |
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what essential functions do proteins do in living cells?
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structure, archetecture, movement of cells, tissues, catalysis, protection, hormones, receptros, lube, transport, storage, fluid retention, contraction, toxins
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how much do proteins weigh?
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10-1000kD
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what is a conjugated protein?
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protein with carbs, lipids, metals, heme, flavins
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are peptide chains of aa's getetically coded?
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yes
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how many aa's are there?
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20
19aa's 1 ia |
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what is a derived aa?
|
modified aa's after being incorporated into chain
ex: cystine, hydroxyproline, carboxyglutamate, desmosine, isodesmosine |
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which are the S containing aa's?
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cysteine and methionine
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which aa's have uncharged side chains?
|
asparagine
glutamine serine threonine |
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which aa's are alcohols?
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serine
threonine |
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which are the acidic aa's?
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aspartate
glutamate |
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which are the basic aa's?
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histidine
arginine lysine |
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what is protein digestion?
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degradation of proteins by proteases into small peptides and free aa's
-free aa's can be reused or used as fuel |
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what are endoproteases?
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proteases that cleve in the interior of a sequence
very specific usually ex: between glutamine and lysine |
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what are exoproteases?
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chew up the protein from the ends, nonspecific
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what are the classifications of proteins?
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simple-only aa's
conjugated- aa's and carbs, lipids, metals fibrous- keratin, collagen, not soluble globular- soluble, spherical, enzymes and ab's |
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how is collagen synthesized?
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tropocollagen's lysyl residues oxidyze to aldehydes
aldehydes cross-link with amino groups of other lysyl residues makes collagen strong |
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what cofactors are needed for lysyl oxidase to turn lysine into allysine (aldehydes)
|
B6 (pyridoxine) and Cu
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what are the main aa's in collagen?
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Gly
Pro OH-Pro |
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what is the result of Cu deficiency in pigs?
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collagen disorders
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what does beta-aminoproprionitrile do?
|
found in sweet peas
inhibits lysyl oxidase which leads to osteolathyrism |
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what vitamin is required for the hydroxylation reaction of proline and lysine?
|
Vit C
leads to scurvy |
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who can't synthesize Vit C from glucose?
|
monkeys
GP's humans fish |
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what are the symptoms of scurvy?
|
decreased wound healing
osteoporosis hemorrhaging anemia bruise easily |
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what is the result of collagen dysplasia?
|
skin fragility
slow wound healing abnormal scar formation excessive bruising bleeding joint lazity osteogenesis imperfects osteroprosis viscera rupture (esp spleen) artery rupture |
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who does Ehlers-Danlos Syndrom affect?
|
people
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who does Cutaneous asthenia affect?
|
dogs and cats
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who does dermatosparaxis affect?
|
cattle
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what happens to collagen as one ages?
|
cross-linking continues leading to stiffer skin BV, and other tissues
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what is the result of abnormal keratin?
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alopecia from brittle hair, soft nails
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what does retanoic acid do?
|
required to prevent synthesis of high molecular weight forms of keratin and a glycoprotein for mucous thus keeping the epithelial tissues healthy, moist and pliable
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what is epidermolysis bullosa?
|
skin and mucosal blistering due to defective keratin-4 and keratin-5 genes
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what is elastin?
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a yellow, fluorescent protein found in ligmanets and BV walls, skin and CT
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what aa's are found mostly in elastin?
|
Gly and Pro
-lacks Cys and Trp |
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what is Cushing's disease?
|
excessive cortisol, catabolic degradation of elastin, increased fragility of capillary walls, tearing of skin
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what is immotile cilia syndrome
|
abnormal ciliary mvt due to absent or abnormal dynein arms in the adoneme
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what is muscular dystrophy?
|
disease characterized by progressive weakness and degeneration of skeletal muscle that can also cause abnormalities in SA and AV nodes and Purkinje fibers
|
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what causes muscular dystrophy?
|
abnormal dystropin, a structural protein that anchors actin filaments to the extracellular matrix
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ultimately what do enzymes do?
|
decrease activation energy
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what is a holoenzyme?
|
complete enzyme with cofactor
|
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what is an apoenzyme?
|
protein part of the enzyme only
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what are metalloenzymes?
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enzymes that have metallic cofactors
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why does the diet need to include sufficient essential amino acids?
|
because enzymes are subject to turnover and replacement, the body can't store aa's, metals, or vitamins
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how are reaction rates altered?
|
pH
temperature ionic composition of the medium iigands other than substrates of coenzymes |
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what are proenzymes?
|
enzyme precursors that have to be cleaved before the catalytic activity appears
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what is a zymogen?
|
inactive proenzymes
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what are isozymes?
|
the different molecular forms of enxymes that have different primary structure but catalyze the same reaction; enzymes with the same primary structure but differing in post-translational modification
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how is enzyme activity expressed?
|
amt converted: umol substrate/min
specific activity: units/mg protein turnover number: units/mole enzyme |
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what is enzyme inhibition?
|
anything that alters or interferes with substrate/activation site interaction
|
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what is reversible inhibition?
|
competitive
non-competitive allosteric |
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what is irreversible inhibition?
|
denarutation
covalent modification |
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what is product inhibition?
|
regulation of a pathway
ummmmm look this up |
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what is feedback control?
|
positive
negative |
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constitutive vs inducible
|
???
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what is the enzyme cascade?
|
the catalytic efficiency of one enzyme is influenced by another enzyme
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