liveonearth (liveonearth) wrote,
liveonearth
liveonearth

Bile Salt Formation

What the first step in making bile?
7 alpha hydroxylation of cholesterol
this is the rate limiting step, inhibited by presence of bile acids
cyp enzyme requires iron 2+ and NADPH, and forms water

What happen to iron in the reaction?
Fe2+-->3+


What steps follow the initial hydroxylation?
reduction of the 4,5 double bond, oxidation of the side chain

7 alpha-hydroxycholesterol is converted eventually to what two acids?
chenocholic and cholic acid
chenocolic has hydroxyls at positions 3 and 7
cholic has them at 3, 7, 12

What hormone stimulates bile release?
CCK

What are the conjugates used?
glycine or taurine
bile acids not conjugated
bile salts are conjugated

What's the pK of bile salts?
pH ~6

How much of bile salts are recycled?
95%
5% are excreted because intestinal bact deconjugate, dehydroxylate
this makes them less soluble

GILBERT'S SYNDROME
AKA Gilbert-Meulengrachts syndrome
most common hereditary cause of increased bilirubin
in 5-10% of pop
harmless jaundice
dt reduced activity of the enzyme glucuronyltransferase
which conjugates bilirubin and some other lipophilic molecules
conjugation renders the bilirubin water-soluble, after which it is excreted in bile into the duodenum
Tags: cholesterol, digestion, gall bladder, lipids, liver
Subscribe

  • QotD: Do Unto Others

    Do unto those downstream as you would have those upstream do unto you. -Wendell Berry

  • QotD: If you don't

    "If you don't do it this year, you will be one year older when you do." -Warren Miller

  • Scoring for Whitewater Readiness Quiz

    SCORING FOR THE WHITEWATER READINESS QUIZ Take the grand total of all the numbers you wrote down while taking the quiz and subtract 11. Done.…

  • Post a new comment

    Error

    Comments allowed for friends only

    Anonymous comments are disabled in this journal

    default userpic

    Your reply will be screened

    Your IP address will be recorded 

  • 0 comments