Lecture 3 - 1/5 Flashcards
Heterotropic effectors
Where the allosteric regulators bind at sites other than the active site.
Homotropic effectors
This causes the S-shape of the allosteric M-M plot
feedback inhibition
The last step controlling the beginning step (the committing step)
homeostasis
the ability to maintain a steady level of intermediates.
Two conformations of concerted model of allosteric regulation
T (tense/taut) state - most stable
R (relaxed) - binds substrate the best
Activators stabilize T or R state
R state. Shifts M-M curve to left
competitive inhibitors
bind at the active site. they block access to substrate
uncompetitive inhibitors
bind to ES complex
noncompetitive inhibitors
bind to either E or ES
Porphrin rings
have a metal in the middle and 4 pyrrole rings around the outside
Cooperative behavior
Similar to homotropic behavior in allosteric enzymes, but in a protein (hemoglobin)
Puranose
six-membered ring with an oxygen
Furanose
five-membered ring with an oxygen
Anomer
up/down configuration (alpha-beta)
Glycosyltransferases
add sugar to growing chain (at non-reducing end)
Glycosidases
Cleaves sugars
linkages of cellulose
beta-1,4 linkages
linkages of starch and glycogen
alpha-1,4 and a-1,6 linkages
glycoprotein
mostly protein. found in cell membrane
proteoglycans
mostly sugar. have aminoacetyl groups, that attract a lot of water. Thus, they are viscous in solution because the water doesn’t flow very well. Found in saliva, lungs.
N-linked glycoproteins
formed by the condensation reaction with asparagine, connected by N. The chain of mannose sugars gets assembled ahead of time and the linked to asparagine en masse. N-liked polysaccharides are high-mannose.
O-linked glycoproteins
formed by the reaction with the O on the side-chain from serine or threonine. The sugars are added to the glycoprotein one at a time.
Job of proteoglycans
Take up volume in extra-cellular space to provide a cushion. Cartilage is mostly extra-cellular matrix
Zymogen
An enzyme in its inactivated state. It can be modified by other enzymes or a change in its environment to take on the activated state.
Mucin
Are often lubricants because of their high percentage of aminosugars, which makes them viscous. Similar to proteoglycans.
