M+C enzymes Flashcards
how do you regulate enzyme abundance?
feedback inhibition
name 4 post transitional modifications
1) addition of functional groups
2) structural changes
3) changes to an amino acid
4) addition of proteins or peptides
what is the advantage of PTMs
they increase protein diversity increasing the complexity of the proteome (cost effective)
what are moonlighting proteins
when proteins have 2 or more functions
what is a glycogen granule made up of
30,000 glucose units and a core protein of glycogenic
what is the shape of a glycogen granule and the advantage of its shape
highly branched making it more soluble and can be degraded/synthesised much quicker
what is a common PTM in eukaryotes?
kinase/phosphotase cascades acting as amplifiers adding and removing phosphate groups from proteins
what do alpha and beta cells produce and where are they found?
alpha = glucagon
beta = insulin
found in the islets of langerhan in the nucleus
what is the role of insulin?
decreasing blood glucose by stimulating glucose uptake and inhibiting the breakdown of glycogen and the glucose pathway
what is the role of glucagon?
increases blood glucose by breaking down glycogen stores and increases the rate of glycolysis in muscles
what is the role of adrenalin (epinephrine)?
hormone also involved in glucose degredation
where is adrenaline produced?
the adrenal glands
which cells have receptors for glucagon and insulin?
liver cells
what is a special feature of adrenalin?
can cause glycogen breakdown without passing through the plasma membrane
how is glycogen synthesis regulated?
by protein phosphorylation
what are the 2 forms of glycogen synthase?
A) dephosphorylated and active
B) phosphorylated by protein kinase A and inactive
what is protein kinase A activated by?
cyclic AMP
what causes the formation of CAMP?
the binding of adrenalin or glucagon activates adenyl cyclase pathway
what is the role of phosphodiesterase?
converts cAMP to AMP
what is glycogen phosphorylase a?
active phosphorylated form on the enzyme that degrades glycogen
what is glycogen phosphorylase b?
dephosphorylated inactive form
what is the role of phosphorylase kinase?
phosphorylates glycogen phosphorylase a
insulin produces protein phosphatase which does what?
dephosphorylates 3 enzymes which inactivates glycogen degradation and activates glycogen synthesis
what are 3 features of secondary messengers?
1) small
2) watersoluble
3) spread easily by diffusion
what is transduction?
when a small number of extracellular signal molecules are able to produce a large cellular response in a phosphorylation cascade
