Exam 1 Flashcards
Most folate in the body is found in the reduced form of ________ which is oxidized by_________.
Tetrahydrofolate (FH4)
dihydrofolate reductase
Three Structural Features of Folate and their importances
- Peteridine Ring: site of oxidation/reduction
- Para-aminobenzoic acid (PABA): sulfa drugs are analogs of this, which are antimicrobial. (bacteria make folate)
- Polyglutamate Tail: cleaved to n=1 in brush border of lumen
Diseases that can damage intestinal mucosa and, thus inhibit folate synthesis? (3)
- Crohn’s Disease
- Alcoholism
- Celiac Disease
Cause of a functional folate deficiency? Note: serum levels seem fine.
Stuck in most reduced form (N5-methyl-FH4)
What is the major carbon source for the one carbon pool (which forms FH4)
Serine
FH4 is needed for purine synthesis!! <— needed for cell division
Major source of Vitamin B12?
Meats
Major source of Folate?
Leafy Green Vegetables
Deficiency of intrinsic factor which leads to Vitamin B12 deficiency.
Pernicious Anemia
Three possible routes of Vitamin B12 deficiency?
R-Binder Absent
Intrinsic Factor Deficient
Dietary Decrease
Name of test which helps specify the cause of a Vitamin B12 deficiency. (Involves several steps and urine collection)
Schilling Test
What is SAM made up of? (~2)
Methionine (made from B12)
ATP
Function of SAM?
Important in Neurotransmittters Synthesis
Adds methyl groups to nitrogen or oxygen atoms (it is converted to SAH when it does this)
Function of Folate?
The one Carbon Pool (FH4/Purine Synthesis)
Adds one carbon groups (from serine) to carbon or sulfur atoms
Pt. with limited DNA synthesis, and RBCs do not work properly causing anemia. Can be caused by B12 or Folate deficiency. Enlarged Cells.
Megoblastic Anemia
Fancy term for “made from scratch”
de novo
Molecule that contributes both carbons and nitrogen to purine synthesis?
Glycine
Disease where enzyme involved in protein salvage is defective and purines are not salvaged and instead converted into uric acid?
Lesch-Nyhan syndrome
Disease with is associated with inability to produce T or B cells due to build up of toxic materials, which is caused by lack of protein salvage. (lymphocytes are known to use the salvage pathway for synthesis)
Adenosine Deaminase Deficiency
What is an important enzyme in the production of uric acid from the breakdown of GMP and AMP (purine degradation)
Xanthine Oxidase - xanthine is the product of AMP/GMP degradation. It is then made into uric acid and hopefully excreted.
Inhibition of the enzymes which help produce OMP and UMP causing an excess of Orotic Acid in the urine is called?
Orotic Aciduria
