Lecture 11 Flashcards
How many amino acid transporters are there at the BBM?
7
How many amino acid transporters are there at the BLM?
9
What system transports cationic amino acids at the BBM?
b0,+
What does the lower case b mean?
It is sodium independent transport.
What are two examples of amino acids transported?
Lysine and arginine
What other compound is moved by this system?
Cystine
What type of transport is this?
An electrogenic antiporter, it moved cationic amino acids in and effluxes neutral amino acids.
What are the two components of this transporter?
rBAT and BO+AT
Which one anchors the other?
rBAT anchors BO+AT to the membrane.
This system is defective in:
Cystinuria
How are the dibasic amino acids transported across the basolateral membrane?
By y+L. This is sodium dependent. It is electroneutral as the positive amino acid is exchanged for a sodium, and a neutral amino acid.
What are the two components of y+L?
CD98 and y+LAT1.
Lysinuric protein intolerance occurs because of a defect in what?
y+LAT1.
Why is lysinuric protein intolerance worse than cystinuria?
Because the dibasic amino acids are trapped inside the cell as they cant cross the BLM.
What system transports neutral amino acids across the apical membrane?
B0
What is B0
Electrogenic amino acid transporter than brings sodium in too. Also called BOAT1
What disorder is BOAT1 defective in?
Hartnup disease.
What is niacin?
The precurser for tryptophan
Is sodium important for transport of alanine?
Yes, alanine is a neutral amino acid so it transported by the sodium dependent B0 system
Glycine and proline are absorbed by
PAT1
A general amino acid urea like Fanconi syndrome shows what in the urine?
Proline
The R240Q residue of BOAT1 sits where?
on the outside of the protein distant from the catalytic site but used for linking with co-expressed proteins.
What protein does BOAT1 attach to?
ACE2
