Chapter 5: Enzymes Flashcards
What proteins speed reactions up?
enzymes
In competitive inhibition where do the substrate and inhibitor bind
same site, active site; Vmax stays the same
In noncompetitive inhibition where do the inhibitors bind?
allosteric site (different site); may cause a change in active site and therefore, substrate cannot bind so Vmax decreases
Why do we prefer competitive inhibitors to non-competitive inhibitors?
They are reversible.
Wen you give electrons away it is called ____
oxidation
When you accept electrons it is called
reduction (OIL RIG) oxidation is loss, reduction is gain
What is oxidative phosphorylation?
When NADH, FADH2, and electrons are made into ATP (energy)
Where does the NADH come from in the oxidative phosphorylation?
from pyruvate dehydrogenase, and 3 enzymes in citrate cycle : isocitrate dehydrogenase, alpha-ketoglucarate dehydrogenase, and malate dehydrogenase
Where does FADH2 come from in oxidative phosphorylation?
succinate dehydrogenase
What coenzyme is needed at the II of ETC?
coenzyme Q
What is an electron carrier from III to IV in ETC?
cytochrome C
What is a coenzyme of Complex IV?
Copper
What occurs at Complex V?
phosphorylation (ADP—ATP)
What common drug for cholesterol destroys Coenzyme Q and Cytochrome C?
statins
What drug can block Complex 1?
Rotenone (pesticide)
What drug can block Complex IV?
CO, CN, Chloramphenicol
Why will the Hb saturation be normal in carbon monoxide poisoning?
Because CO is a competitive inhibitor of O2; that is why to overcome CO we must give 100% O2 (increase substrate, up Km).
What kinds of bacteria does chloramphenicol cover? Why don’t we like to use it?
all gram +, simple gram -, rickettsia; affects all rapidly dividing cells by blocking the 50s subunit and its peptidyl transferase; causes aplastic anemia and gray baby syndrome
Compounds that grab protons in ETC and drag them back into the matrix and stops ATP synthesis, releasing a lot of energy are called __________.
uncouplers
Examples of uncouplers
aspirin, succinylcholine (malignant hyperthermia), haloperidol (neuroleptic malignant syndrome), DNP (dinitrophenol) pesticide, free fatty acids
Tx for malignant hyperthermia and neuroleptic malignant syndrome?
dantrolene: stabilizes sarcoreticular and ryandine arm so no Ca for contraction
What does uncoupling do to the liver?
shrinks it
What conditions cause microsteatosis of liver?
pregnancy, tylenol poisoning, Reye’s syndrome
What conditions cause macrosteatosis of liver?
obesity (NAFLD); and alcohol
What kind of enzyme phosphorylates a stubstrate using ATP?
kinase
What is a cofactor for kinase?
magnesium
What kind of enzyme phosphorylates a substrate using free phosphate?
phosphorylase
What kind of enzyme creates an isomer from a substrate?
isomerase
What has the same chemical makeup and structure but differ around one chiral carbon?
epimer
What kind of enzyme makes epimers?
epimerase
What kind of enzyme moves a side chain from one carbon to another carbon?
mutase
What kind of enzyme transfers a side chain from one substrate to another?
transferase
What kind of enzyme transfers amino acids from or onto amino acids?
transaminase
What kind of enzyme cuts carbon-carbon bonds and must use ATP to do it?
lyase
What kind of enzyme uses carbon dioxide to create a carbon-carbon bond but uses biotin as a cofactor?
carboxylase
What kind of enzyme is used to stack substrates together to create a product?
synthase
What kind of enzyme uses ATP to stack substrates together to create a new product?
synthetase
What kind of enzyme uses a cofactor to take hydrogens off substrates?
dehydrogenase
What kind of enzyme uses water to break bonds?
hydrolase
When a sulfur bond is broken in the reaction, what word do we add in front of enzyme name?
Thio–
