Proteins 2 Flashcards
What are the 3 types of proteins?
Glycoproteins
Lipoproteins
Metalloproteins
Define glycoproteins.
Any class of proteins which have carbohydrate groups attached to the polypeptide chain.
Give 2 examples of glycoproteins.
Immunoglobulins
Blood group determinants
What is glycosylation?
A process which occurs in the endoplasmic reticulum and golgi apparatus. It’s roles are: protein stabilisation, effect solubility, protein orientation, signalling and cell recognition.
Define lipoproteins.
When proteins and lipids bond together and transport water and insoluble fats/cholesterol in the blood.
Define good cholesterol.
High-density lipoprotein, transported back to the liver.
Define bad cholesterol.
Low-density lipoprotein, get caught in arteries and can lead to heart attacks.
Define metalloproteins.
Protein molecules with a bound metal ion, i.e haemoglobin. One third of proteins need a metal ion for their specific role.
Haemoglobin is made up of…
2 alpha chains, 2 beta chains and an iron heme group.
What is cooperative binding?
When the binding of a molecule to one subunit changes the affinity of the other subunits to the molecule.
Define collagen.
Fibrous proteins which make up about 30% of the total proteins in humans. Strong and composed of repeated unit.
How is collagen formed?
Polypeptides coil and form a helix and then 2 more join in to form a triple helix and are held together by hydrogen bonds. These can then form fibrils.
What are LDL receptors?
Glycoproteins. They are present on the surface of all cells causing the internalisation of LDL.
What are the 5 LDL receptor mutation effects?
No receptors produced Receptors never reach cell surface Receptors can't bind to LDL Receptors don't internalise on binding to LDL Receptors don't release LDL
Define cryoglobulins.
Proteins which precipitate and solidify when the temperature gets less than 37 degrees celsius.
