Week 5 - liver biochem

Question 1

pit cells

Answer 1

liver resident lyphocytes (NK cells - protect against viruses and tumor cells)

Question 2

phase I vs II in detoxifying xenobiotics and metabolites

Answer 2

I - add hydroxyl groups to substrates - catalyzed by P450 enzymes, all use NADPH (for the hydride) and O2 to add the OH group

II - add sulfate, methyl groups, glutathione, or glucuronate to the hydroxyl group

Question 3

what metabolizes statins

Answer 3

cyp 3A4

Question 4

CYP2E1 converts this chemical found in plastics into a reactive epoxide that damages the liver, causing angiosarcoma

Answer 4

vinyl chloride

Question 5

donor of sulfur in biochem shit

Answer 5

3’ phosphoadenosine 5’ phosphosulfate

aka PAPS

Question 6

in large doses, what is acetominophen metabolized by

Answer 6

CYP2E1

creates NAPQI

Question 7

PGM1

Answer 7

phosphoglucomutase 1 interconverts glucose 1-p and glucose 6-p

Question 8

what carries excess nitrogen to the liver

Answer 8

primarily alanine and glutamine (alanine only takes nitrogen from an amino acid, glutamine can take fre ammonium (NH4 plus glutamate = glutamine))

Question 9

first step of urea formation

from glutamine

from NH4

Answer 9

from glutamine, glutaminase is used to take off the nitrogen - happens in periportal hepatocytes

then CO2 and NH4 combine via carbamoyl phosphate synthetase I (needs cofactor N-acetylglutamate)

Question 10

what event ocurs after Wnt binds its receptor

what is the application of Wnt binding its receptor in the perivenous hepatocyte

Wnt stands for wingless-type MMTV (mouse mammary tumor virus) integration site

Answer 10

beta-catenin translocates to the nucleus. in the perivenous hepatocytes, this signals for glutamine synthase to be expressed

Question 11

what happens if you exceed the capacity of carbamoyl phosphate synthase in the liver (by, lets say, taking a whole tub of protein powder to get swole as fuck)

Answer 11

Glutamine synthase in the perivenal hepatocytes fixes the ammonia back to glutamine, so that you don’t dump ammonia into the blood)

Question 12

where is glutaminase in the liver

where is glutamine synthase

Answer 12

glutaminase - in the periportal hepatocytes (where new blood is entering the liver)

glutamine synthase - in the perivenous hepatocytes (where blood is leaving the liver)

Question 13

what happens to beta catenin when Wnt is not active

when Wnt is active?

Answer 13

it gets phosphorylated and degraded by the proteasome

Wnt stops the enzyme that phosphorylates beta-catenin

Question 14

two names of ketone bodies

Answer 14

acetoacetate

beta-hydroxybutyrate

Question 15

decyclized heme is bound to what to make conjugated bilirubin

Answer 15

added to 2 glucuronates