Structure of threonine
Same as serine except OH and CH3 both come off CH2
How can you break a peptide bond?
Add strong base
Proteins w/ covalently attached molecules
- Attached molecule = prosthetic group (metal ion, vitamin, lipid, carbohydrate, nucleic acid)
Mixed inhibition = inhibitor binds to E and ES w/ (equal/unequal) affinity
Enzyme devoid of necessary cofactor = ______
- Catalytically inactive
Breakdown of single molecule into two molecules
- Often forms cyclic compounds or double bonds
- Does not add water and does not transfer electrons
Joins two large biomolecules together
Epimer = subtype of diastereomers that differ at exactly 1 chiral carbon
Anomer = subtype of epimer that differ at anomeric carbon
Number of glucose chiral centers
4 => 16 stereoisomers
React ethanol w/ glucose => ?
- Replace hemiacetal w/ acetal
Beta-amylase = cleaves maltose at non-reducing end => maltose exclusively
Alpha-amylase = cleaves maltose anywhere => maltose, glucose, and polysaccharides
Any sugar w/ hemiacetal ring
- Has free aldehyde group or ketone group (that can tautomerize)
- One anomeric carbon in molecule is NOT involved in anomeric bond and is free to be oxidized under H2O/Br => forms acetal/ketal
- Ex. all monosaccharides b/c all have aldehyde group, maltose, lactose, cellobiose
Amylose = linear, all alpha 1-4
Amylopectin = has branches, alpha 1,6
Hemiacetal vs. Acetal
Hemiacetal has OR, H, R, and OH group (like monosaccharides)
Acetal has no OH group but OR, H, R and OR group (polysaccharides)
One terpene = ____ isoprenes
One terpene = 2 isoprenes
Autocrine + paracrine hormones that regulate cAMP
Saponification = ______ hydrolysis of triacylglycerol using strong ______
Ester hydrolysis using strong bases
Does not get hydrated => does not have extra weight on it (which would take away energy density)
Highly reduced => can produce more energy
More saturated fatty acids => (more/less) fluid solution
Less fluid b/c can pack more tightly and form more noncovalent bonds
- Higher melting point for saturated than unsaturated
How do you hydrolyze an amide?
Add H2O and heat to form COOH from amide
6 carbons => forms 5 carbon ring (furanose)
Is longer DNA more/less stable?
More stable b/c more H bonds throughout
Unfolding of proteins = (cooperative/noncooperative) => shape of curve is ________
Cooperative => sigmoidal
Cannot be oxidized b/c no hemiacetal/hemiketal present
- Both anomeric carbons are involved in anomeric bond
- Ex. sucrose (glucose + fructose)
Catalyzes formation of peptide bond b/w incoming AA and growing polypeptide chain
What does RNA Pol I do and where is it?
Located in nucleolus
Compounds that contribute to membrane fluidity do what?
Lower melting point or disrupt crystal structure
- Ex. cholesterol, unsaturated lipids
Which glycolysis enzymes catalyze irreversible reactions?
What enzymes are used instead in gluconeogenesis and what are they activated by?
Glucokinase (liver) and hexokinase (muscle), PFK-1, and pyruvate kinase
- Pyruvate carboxylase - converts pyruvate to OAA => PEP
- Activated by acetyl CoA
- Fructose 1,6 bisphosphatase - converts F16BP to F6P
- Activated by ATP and glucagon
- Glucose 6 phosphatase - converts G6P to glucose
- Only found in ER of liver
Pyruvate dehydrogenase is stimulated by _____ and inhibited by _______
Stimulated by insulin
Inhibited by Acetyl Co-A
What does glycogen synthase do?
Creates alpha 1-4 glycosidic linkages b/w glucose molecules
- Activated by insulin in liver and muscle
Breaks alpha 1-4 links b/w glucose in glycogen => catalyzes glycogen breakdown
- Activated by glucagon when glucose is gone
Pentose-phosphate pathway rate-limiting enzyme
- Activated by NADP+ and inhibited by NADPH and insulin
Pyruvate can form what three molecules?
OAA (gluconeogenesis via pyruvate carboxylase)
Acetyl-CoA (TCA via pyruvate DH)
What does citrate regulate?
Negative allosteric regulator of PFK1 (which catalyzes rate-limiting step of glycolysis)
What does pentose phosphate pathway do?
Generates NADPH using G6PDH => reduces glutathione (antioxidant)
- PPP mitigates oxidative stress
- NADPH also synthesizes lipids/cholesterol, produces bleach in lysosomes in addition to mitigating oxidative stress
Name the rate-determining enzymes for:
Glycolysis = PFK1
Gluconeogenesis = F16BP
PPP = G6P dehydrogenase
Glycogenesis = glycogen synthase