Lab 4 Flashcards
(48 cards)
Define Enzymes
enzymes are proteins that act as catalysts in specific biochemical reactions, including the metabolism of drugs
explain the fate of drugs that are metabolized
they have undergone a chemical change that will dictate their pharmacological and toxicological profiles
true or false
enzymes involved in drug metabolism also metabolize endogenous substances such as hormones, vitamins, and lipids
TRUE
_____ is the primary site of metabolism for most drugs
the liver
as mentioned, the liver is the primary site of metabolism for most drugs.
name other significant organs for drug metabolism
kidneys
lungs
GI tract
blood
nervous tissue
skin
define first pass metabolism
the ability of the liver (and extrahepatic tissues) to metabolize drugs before they reach systemic blood circulation
where are cytochrome P450 enzymes found?
in liver cells in the membrane of the endoplasmic reticulum
name 2 examples of endogenous molecules
nutrients and hormones
name 2 examples of exogenous molecules
drugs and xenobiotics
the metabolism of both endogenous and exogenous molecules are classified as…..
phase 1 and phase 2
do phase 1 and phase 2 metabolism occur in most tissues?
yes (liver, kidney, skin, and lungs)
but the LIVER is the PRINCIPAL SITE for DRUG METABOLISM
the primary purpose of liver metabolism is __________
drug inactivation aka detoxification
the primary purpose of liver metabolism is drug inactivation (detoxification)
what is a concern with this
some drug metabolites ARE pharmacologically active and sometimes may even be more potent than the parent compound
Prodrugs are designed for….
conversion to an active moiety in the liver
what can you say about molecules that are very lipophilic?
they need to be converted to a hydrophilic molecule to facilitate their excretion and/or to increase their reactivity with cellular macromolecules such as protein and DNA
TRUE OR FALSE
drugs always undergo phase 1 and phase 2 of metabolism
FALSE
they may only undergo phase 1 or 2 depending on their functional groups and polarity
what does the S9 fraction contain?
both phase 1 and phase 2 drug-metabolizing enzymes
phase 1 = cytochrome P450 in the microsomes
phase 2 = cytosolic fraction
_______ is a valuable tool to study the in vitro metabolism of drugs.
explain
S9 fraction bc it contains both phase 1 (cytochrome P450 in the microsomes) and phase 2 (cytosolic enzymes) drug metabolizing enzymes
how can you predict the metabolic fate of the compound of interest? (drug)
by incubating it with the S9 fraction
the quality of the S9 fraction and other enzyme extracts is generally based on……..
the enzymatic activity present in 1mg of protein
when COMPARING enzyme extracts, the concentration of the protein in the extract must also be analyzed
true or false
there are few types of assays one can use to determine the protein concentration of a sample
FALSE – there are many types
as mentioned, there are many types of assays one can use to determine the protein concentration of a sample.
when deciding which type of assay, what 4 things should you take into account?
-how sensitive the assay is
-how difficult the assay is to run
-does the sample contain
compounds that interfere with the assay?
-how long the assay takes and expenses of reagents
How do you determine the concentration of an unknown sample?
a standard curve must be generated
comprised of data points of increasing known concentrations of proteins and their measured absorbance values. in protein assays, this trend will be linear
SO the equation of the trendline can be used to predict the concentration of your unkown
“the equation of the trendline of a standard curve can be used to determine the protein concentration of your unknown.”
what is the term for this?
interpolation
