Proteins 2 Flashcards
What are 3 other types of protein?
glycoproteins
lipoproteins
metalloproteins
What are glycoproteins?
compounds composed of protein and carbohydrate
What is an example of a glycoprotein?
immunoglobulins
blood group determinants
What is glycosylation?
process that occurs in the ER and Gologi apparatus that adds a sugar onto the protein via an amino acid
What is the function of glycosylation? (5)
- protein stabilisation
- affect solubility
- protein orientation
- signalling
- cell recognition
What is HbA1C?
complex of haemoglobin and glucose (a glycoprotein)
What is the significance of HbA1C?
the higher the level of HbA1C, the worse the diabetic control
What is the function of lipoproteins?
the transport of water insoluble fats and cholesterol in the blood
Give an example of a lipoprotein.
HDL, LDL
What is a metalloprotein?
protein molecule with a bound metal ion
What are the functions of metalloproteins? (4)
- enzymes
- signalling
- storage
- transport
What are the functions of globular proteins?
- enzymes
- hormones
- transporters
- structural function e.g tubulin
How does haemoglobin transport 02?
haem group at the centre of each polypeptide chain binds one molecule of oxygen so that each molecule of haemoglobin can bind 4 molecules of oxygen
What kind of binding does the oxygen carrier haemoglobin exhibit?
co-operative binding
the binding of 02 to one subunit causes a conformational change that results in the binding of another molecule of oxygen in another subunit
What causes sickle cell anaemia?
single base chain in DNA coding for B chain of haemoglobin
results in glutamic acid (hydrophilic) to be replaced with valine (hydrophobic)
What type of protein is collagen?
fibrous
What is the structure of collagen?
polypeptide coils to form a helix
3 polypeptides then coil around each other and are held together by hydrogen bonds
What happens to cause scurvy?
vitamin C deficiency resulting in weaker collagen being produced
What happens to cause osteogenesis imperfecta?
glycine substituted for larger amino acid
weakened and brittle collagen produced
What are LDL receptors and what do they do?
- glycoprotein
- cause internalisation of LDL
What is familial hypercholesterolemia?
an autosmal dominat disorder caused by a mutation in the LDL receptor gene and results in elevated LDL concentrations in blood
can lead to early cardiovascular disease
