BCH ch 2-6

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which aa's have 4 enantiomers?: isoleucine
threonine
which aa is the simplest aa known?: glycine
how do aa's exist at pH 7.4?: dipolar zwitter ions
which aa is the hydroxylated form of alanine?: serine
where are hydrophilic aa's found?: on the surface of proteins
which aa is found in the bends of folded polypeptide chains?: proline
is arginine an aa that is hydrophobic or hydrophilic?: hydrophilic
which of the aa's has branched side chains?: leucine
isoleucine
valine
which are the aromatic aa's?: phenylalanine, tyrosine, tryptophan
what is the most abundant protein in the mammalian organism?: collagen
vitamin C is required in the formation of which aa?: hydroxyproline
which modified aa is a constituent of elastin?: isodesmosine
which modified aa is associated with blood coagulation?: gamma-carboxyglutamate
which aa is used in the hepatic conjugation of bile acide?: taurine
name an inhibitory NT in the brain: gamma-aminobutyrate and glycine
is alanine an essential aa in young cats?: no
which aa's are essential in cats?: methionine
phenylalanine
taurine
arginine
which aa's are routinely oxidized in muscle tissue?: branched chain aa's:
leucine
isoleucine
valine
do benzodiazepines (valium) act by blocking the action of GABA at post-synaptic receptor sites?: no
is the formation of highly organized amyloid aggregates a generic property of polypeptides?: yes, it may be
what directly influences the secondary, tertiary, and quaternary structure of proteins?: primary structure
how is the secondary structure of aa's held together?: H-bonds between carboxyl and amino groups of the peptide bond
are disulfide bonds part of the secondary structure of all mammalian proteins?: no
what is the tertiary structure of a protein?: the overall 3D arrangement of its polypeptide chain
how are alpha helixes stabilized?: H-bonding between amide H's and carbonyl O's of different peptide bonds
how are the beta pleated sheets stabilized?: H-bonding between separate chains that run either parallel or antiparallel to one another
What do chaperones do?: guide polypeptide chains to their tertiary structure while the primary sequence is being formed
what level of organization does protein denaturation affect?: affect all levels of protein structure
what do globular proteins look like: spherical and hydrophilic
what is joined in a peptide bond?: alpha carboxyl group of one aa and the alpha amino group of another aa
how many aa residues are there in the active form of insulin?: 51
what are coenzymes?: small, organic, non-protein molecules that carry chemical groups between enzymes
what do phosphatases do?: remove phosphate groups from phosphorylated compounds
which enzyme is activated irreversibly?: pepsinogen
what is the characteristic enzymatic activity in the digestive lumen?: hydrolysis
how many different types of enzymes are normally present in a mammalian cell?: 2000
what do hydrolases catalyze?: the cleavage of bonds between carbon and some other atom by the addition of water across the bond
what hormone acts by increasing enzyme synthesis in its target cells?: cortisol
what is urease?: an enzyme found in microbes of the rumen
what do synthases do?: stimulate synthesis without using ATP
which suffix refers to an enzuyme?: -ase
which is the variable that measures the affinity of an enxyme for its substrate?: Km (read K sub m)
what are temperature and pH known to affect?: Km and Vmax
what happens to the maximal velocity of an enzyme-catalyzed reaction in the presence of an irreversible inhibitor?: decreased in the presence of an irreversible inhibitor
which tissue type has the highest concentration of MB dimer for creatine phosphokinase?: heart
which therapeutic inhibitor is considered to be a suicide substrate?: aspirin
what is the y-intercept on a Lineweaver-Burk plot?: 1/Vmax
what is the Mechaelis-Menten equation?: V=Vmax[S]/(Km+[S])
what are competitive inhibitors and what do they do?: 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
which type of enzyme inhibitor is known to affect both Vmax and Km?: uncompetitive
which aa is needed for hepatic tyrosine biosynthesis?: phenylalanine
which aa is needed for cysteine formation: methionine
which aa is needed for serotonin and melatonin formation?: tryptophan
which amino acids are considered "essential" in adults?: leucine
isoleucine
valine
taurine (cats)
threonine
lysine
phenylalanine
tryptophan
methionine
which amino acids are considered "essential" in young animals?: histidine
arginine
glycine (chickens)
how do G-proteins work as control proteins?: 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
what are 2 example of irreversible proteolytic enzymes found in the pancreas?: exopeptidases
endopeptidases
what is ALKALINE PHOSPHATASE?: enzyme that removes PO4 groups,
most active at alkaline pH
what are the most imporatant ALP serum sources?: liver (L-ALP) bile duct cells
bone (B-ALP) osteoblasts
leukocytes
dog liver (C-ALP)
what does an elevated ALP indicate?: L-ALP: bile duct damage
B-ALP: bone growth/fractures
Leuk-ALP: increase in all blood cell types, cancer
what does ASPARTATE AMINOTRANSFERASE do? (AST): transfers an amino group from aspartate->glutamate
oxaloacetate->a-ketogluterate
what are the primary sources for AST?: liver
skeletal/cardiac muscle
what does ALANINE AMINOTRANSFERASE do? (ALT): transfers an amino group from alanine->glutamate
pyruvate->a-ketogluterate
what are the primary sources for ALT?: liver
skeletal/cardiac muscle
what are the tetramer combinations of LACTATE DEHYDROGENASE? (LDH): HHHH
HHHL
HHLL
LLLL
LLLL
what does LDH do?: involved with conversion of pyrvate to lactate and vice versa along with the conversion of NADH to NAD+
what can LDH tell you?: if a cardiac event has taken place
what does GAMMA GLUTAMYL TRANSFERASE do? (GGT): involved in transport of aa's into cells
where is GGT found?: biliary epithelial cells
pancreas
renal tubular cells
mammary glands (some species)
what does elevated serum GGT indicate?: choleostasis, escessive bile back-up (esp in horses)
what does high urine GGT indicate?: injury to renal epithelial cells
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
what does an elevated serum CK3 indicate?: injury to skeletal muscle, muscular dystrophy, myopathy, rhabdomyolysis
what does SORBITOL DEHYDROGENASE do? (SDH): sorbitol + NAD+ <-> fructose + NADH
it is a cytoplasmic protein
what does an elevated SDH indicate?: liver damage
-especially helpful in LA where ALT is not informative
what do AMYLASES do? (AMS): break down starches into smaller polysaccharides
what are the primary sources of AMS?: pancreas
liver
salivary glands (not in Ar or Ca)
what does elevated AMS indicate?: pancreatic disease
pancreatitis

check LPS and TLE
what does LIPASE do? (LPS): break down triglycerides into FAs
what is the primary source of LPS?: pancreas
what does elevated LPS indicate?: pancreatic disease

check AMS and TLE
what does an elevated TRYPSIN-LIKE ENZYME indicate? (TLE): pancreatic disease
what is the primary source of TLE?: pancreas
how is TLE measured?: RIA
what does ALCOHOL DEHYDROGENASE do?: first step in the metabolism of ethanol

deficient in some asian people
what are the consequences of ethylene glycol ingestion?: crystals, cause physical damage, can rupture mito and cells
what are the stages of ethylene glycol toxicity?: 1-CNS
2-Cardio
3-renal

treat with EtOH or fomepizole
what do insecticides target?: AChE

-insecticides usually OP's or carbamates
what are the signs of OP/carbamate poisioning: salivation, lacrimation, urination, defecation, dyspnea, bradycardia, mitosis, fasiculations, tremors, weakness, flacid paralysis, restlessness, hyperactivity, seizures
how can you diagnose OP/carbamate poisioning with tests?: AChE assay
how does penicillin work?: inhibits the synthesis of bacterial cell wall peptidoglycan by inhibiting glycopeptide transpeptidase by binding its active site irreversibly
how do you administer penicillin?: IM, it is unstable in the stomach
how does fosfomycin work?: inhibits synthesis of TB cell wall peptidoglycan by inhibiting the MurA enzyme
what do beta-lactamase inhibitors do?: give new life to old antibiotics
what is etoposide?: a chemotherapy drug that inhibits DNA repair enzymes and therefore increases p53 enzymes
what is an ACE inhibitor?: something that blocks the conversion of ATI to ATII
what do cholesterol statins do?: inhibit key conversion enzymes in conversion
what enzyme does glutothione peroxidase require?: needs selenium

uses glutathione to eliminate H2O2
what is the consequence of Se or Vit E deficiency?: build-up of lipid peroxidases, which in turn causes skel and cardiac musc damage...white fat accumulates in muscles- stiffness, flaccid muscles
what are some of the enzymes that require Cu as a cofactor?: superoxidase dismutase
cytochrome C oxidase
lysine amino oxidase
tyrosinase
what are the symptoms of Vit A deficiency?: vision
skin- keratin
epithelium of resp, repro, dig, tracts- BIRDS
what vitamin is required by cats?: Vitamin A, they can't convert betacarotine to retinol, eat liver
what is the result of a lysosomal storage disease?: accumulation of substrates in lysosomes, leading to physical intracellular crowding
-neurologic consequences, pressure on spinal cord
what is Gaucher?: lsd
what is Fabry?: lsd
what is Tay-Sachs?: lsd
what is Niemann-Pick?: lsd, caused by deficiency of the enzyme acid sphingomyelinase
what are the symptoms of a lysosomal storage disease?: dysmorphic features
psychomotor regression
ocular abnormalities
hepatosplenomegaly
are there some lysosomal storage diseases that are genetic and only effect certain species and breeds?: 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
what is alpha mannosidosis?: an acquired lysosomal storage disease that leads to neuro problems in horses, sheep cattle
what can cause acquired lysosomal storage disease?: locoweed
poison peas
sida carpinifolia
what essential functions do proteins do in living cells?: structure, archetecture, movement of cells, tissues, catalysis, protection, hormones, receptros, lube, transport, storage, fluid retention, contraction, toxins
how much do proteins weigh?: 10-1000kD
what is a conjugated protein?: protein with carbs, lipids, metals, heme, flavins
are peptide chains of aa's getetically coded?: yes
how many aa's are there?: 20
19aa's
1 ia
what is a derived aa?: modified aa's after being incorporated into chain
ex: cystine, hydroxyproline, carboxyglutamate, desmosine, isodesmosine
which are the S containing aa's?: cysteine and methionine
which aa's have uncharged side chains?: asparagine
glutamine
serine
threonine
which aa's are alcohols?: serine
threonine
which are the acidic aa's?: aspartate
glutamate
which are the basic aa's?: histidine
arginine
lysine
what is protein digestion?: degradation of proteins by proteases into small peptides and free aa's
-free aa's can be reused or used as fuel
what are endoproteases?: proteases that cleve in the interior of a sequence
very specific usually

ex: between glutamine and lysine
what are exoproteases?: chew up the protein from the ends, nonspecific
what are the classifications of proteins?: simple-only aa's
conjugated- aa's and carbs, lipids, metals

fibrous- keratin, collagen, not soluble
globular- soluble, spherical, enzymes and ab's
how is collagen synthesized?: tropocollagen's lysyl residues oxidyze to aldehydes
aldehydes cross-link with amino groups of other lysyl residues
makes collagen strong
what cofactors are needed for lysyl oxidase to turn lysine into allysine (aldehydes): B6 (pyridoxine) and Cu
what are the main aa's in collagen?: Gly
Pro
OH-Pro
what is the result of Cu deficiency in pigs?: collagen disorders
what does beta-aminoproprionitrile do?: found in sweet peas
inhibits lysyl oxidase which leads to osteolathyrism
what vitamin is required for the hydroxylation reaction of proline and lysine?: Vit C

leads to scurvy
who can't synthesize Vit C from glucose?: monkeys
GP's
humans
fish
what are the symptoms of scurvy?: decreased wound healing
osteoporosis
hemorrhaging
anemia
bruise easily
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
who does Ehlers-Danlos Syndrom affect?: people
who does Cutaneous asthenia affect?: dogs and cats
who does dermatosparaxis affect?: cattle
what happens to collagen as one ages?: cross-linking continues leading to stiffer skin BV, and other tissues
what is the result of abnormal keratin?: alopecia from brittle hair, soft nails
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
what is epidermolysis bullosa?: skin and mucosal blistering due to defective keratin-4 and keratin-5 genes
what is elastin?: a yellow, fluorescent protein found in ligmanets and BV walls, skin and CT
what aa's are found mostly in elastin?: Gly and Pro

-lacks Cys and Trp
what is Cushing's disease?: excessive cortisol, catabolic degradation of elastin, increased fragility of capillary walls, tearing of skin
what is immotile cilia syndrome: abnormal ciliary mvt due to absent or abnormal dynein arms in the adoneme
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
what causes muscular dystrophy?: abnormal dystropin, a structural protein that anchors actin filaments to the extracellular matrix
ultimately what do enzymes do?: decrease activation energy
what is a holoenzyme?: complete enzyme with cofactor
what is an apoenzyme?: protein part of the enzyme only
what are metalloenzymes?: enzymes that have metallic cofactors
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
how are reaction rates altered?: pH
temperature
ionic composition of the medium
iigands other than substrates of coenzymes
what are proenzymes?: enzyme precursors that have to be cleaved before the catalytic activity appears
what is a zymogen?: inactive proenzymes
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
how is enzyme activity expressed?: amt converted: umol substrate/min
specific activity: units/mg protein
turnover number: units/mole enzyme
what is enzyme inhibition?: anything that alters or interferes with substrate/activation site interaction
what is reversible inhibition?: competitive
non-competitive
allosteric
what is irreversible inhibition?: denarutation
covalent modification
what is product inhibition?: regulation of a pathway

ummmmm look this up
what is feedback control?: positive
negative
constitutive vs inducible: ???
what is the enzyme cascade?: the catalytic efficiency of one enzyme is influenced by another enzyme

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