Proteins and Enzymes Flashcards
Bonds to stabilise a chains
Hydrogen
Primary structure
Sequence of amino acids- held by peptide bonds
Secondary structure
a helix or b sheet
Tertiary structure
internal hydrophobic, external hydrophilic
Quarternary
many polypeptide chains
What forms in the brain of a person with Alzheimers?
insoluble amyloid fibrils
Creutzfeldt Jacob disease
infectious prion protein -> insoluble aggregate
Myoglobin
a helices, O2 store
Haemoglobin
2 a and 2 b chains, O2 transporter, lower affinity to O2
Haem
tightly bound; with protein will keep Fe in ionic form and inhibit CO binding
T state
low affinity for O2- more salt bridges
R state
high affinity for O2
Bohr effect
increase in H+ decreases Hb O2 affinity -> more salt bridges -> T state
Higher BPG at altidude…
low affinity for O2 -> more O2 release
Collagen
Gly, Pro and Hyp alpha helix (gly in centre) Form staggered microfibrils (type I, II and III) with cross links
Collagenases..
break down collagen
Ehlers-Danlos
stretchy skin and loose joints
Osteogenesis imperfecta
type 1 mutation = brittle bones
Scurvy
vit C deficiency = defective collagen
How do enzymes lower activation energy?
Provide groups and better orientation
Active site
specific, 3D, multiple weak interactions
Vmax
Theoretical max rate of reaction
Km
Michaelis constant- affinity
= k2 + k3 / k1
Factor affecting rate of reaction
substrate concentration enzyme concentration temperature pH inhibitors
