Exercises Flashcards
(84 cards)
How can you get in contact with carbon monoxide and why is it toxic?
Incomplete combustion, photochemical reactions in troposphere,
metabolism of hemoglobin, metabolism of xenobiotics
(dichloromethane)
It binds to hemoglobin and blocks the oxygen transfer
How can you get in contact with cyanides and why is it toxic?
ccidentally uptake of cyanide salts, e.g., NaCN or KCN.
Metabolism of nitriles (Bitter almond, crushed flax seeds, improperly
cooked cassava)
It binds to the heme group of cytochrome c oxidase in mitochondria,
and thus blocks the energy transfer (respiration chain)
How can you get in contact with hydrogen sulfide and why is it toxic?
Microbial degradation of organic matters under anaerobic conditions,
swamps and sewers.
Volcano gases, natural gas, thermal springs, human metabolism
Similar as HCN, it binds to the heme group of cytochrome c oxidase
in mitochondria, and thus blocks the energy transfer
What is the toxicity mechanism of 4-fluorobutyl acetate?
It metabolizes into fluoroacetic acid, which then blocks the citric acid
cycle
What is the toxicity mechanism of 1-chloroprop-2-yl butyrate?
The major risk comes from the metabolized α-chloroketone, which is a
strong alkylating agent/electrophile.
How does Dinoseb disturb the cell’s energy production?
It’s an uncoupler, which blocks the production of ATP.
Where do you find nitrite? How can it give rise to toxic effects?
Processed meats, bacons, sausages, fish
Bacterial conversion from nitrate
It can react with amines in the stomach to form carcinogenic N-
nitrosamines
It can oxidize Fe(II) to Fe(III) in the hemoglobin to cause
methemoglobinemia (can be used to treat cyanide poisoning)
Describe the mechanism for how aromatic amines give rise to
methaemoglobinemia.
It can be metabolized into hydroxyamines, which can then oxidize
Fe(II) to Fe(III) in the hemoglobin to cause methemoglobinemia
Hydroxylamines can also generate radicals and electrophilic species
after further metabolism.
What are base pair substitutions, frame-shift mutations, and chromosome
mutations?
What are the downsides of antioxidants?
Phenolics can stabilise radicals but sometimes can act as prooxidants. Some can decrease our bodyguard glutathione, decrease glutathione S transferase activity
What downside of oxidation can happen, and when using p450?
Generating ROS
What are the four types of oxidation?
Alkenes and aromatics (double bonds) can be epoxides
Carbon hydroxylation (not all carbons can be)
Heteroatom oxidation
Oxidation of alcohol and aldehydes
Which enzyme used to oxidise double bond ?
p450 (FeV centre in enzyme)
If you see a double bond what should you think?
Epoxidation
This course we can assume that if it is possible then it will happen, we don’t have to think about what’s more likely
That’s right
Epoxides are…
electrophilic
What is metabolic activation
That’s the molecule becomes toxic when metabolised
benzene can be epoxidised and then be oxidised to
phenol
Not all CH bonds can undergo hydroxylation, which ones can?
Using P450
- allylic hydrogen, the CH bond is connected to a double bond (next to unsaturation)
- next to heteroatom (alfa hydroxylation)
Carbon bound to heteroatom on either side is called a
hemiacetal
Hemiacetal (carbon bound to two heteroatoms) is unstable and will form two products, which?
aldehyde and alcohol/amine/thiol/HCl
What is oxidative dehydrohalogenation?
Carbon hydroxylation when carbon bound to Cl and O
What is oxidative dealkylation?
Carbon hydroxylation when carbon bound to oxygen and oxygen/sulfur/nitrogen, the hydroxylation forms a hemiacetal which is unstable and forms aldehyde and alcohol/amine/tiol
In oxidative dehydrohalogenation, what happens to primary, secondary and tertiary halides?
primary forms alcohol and HCl
secondary forms ketone and HCl
tertiary has no Alfa carbon so no reaction
