Pourmotabbed #3-4 Flashcards
What is the only organ in the body with enzymes for both protein synthesis and degradation?
Liver
AA’s that are broken down to pyruvate or a TCA cycle intermediate are called….
Gluconeogenic
AA’s that b-down into AcCoA are called….
Ketogenic
In general, the 10 nonessential AA’s can be synthesized from….
Glucose
How is Tyrosine synthesized?
Hydroxylation of Phenylalanine
How is Cystine synthesized?
Methionine and Serine
Only the SULFUR of Cys is obtained from Met. The C and N parts come from SERINE.
What is the symbol for tetrahydrofolate?
BH4
Glycine is produced from Serine using what necessary enzymes?
BH4 and PLP
Cystine can form kidney stones due to insolubility, but what forms kidney stones that has to do with glycine?
When glyoxylate can’t be converted to oxalate, oxalate can accumulate and form a precipitate with Ca2+ and form kidney stones.
.
Cystathionase deficiency leads to …..
cystathionuria (benign disorder)
Vitamin B6 deficiency leads to…..
- Transaminase deficiency (AA bdown)
- Cystathionuria
In the synthesis of Cysteine from Serine and Methionine, what enzyme is PLP dependent?
Cystathionase - converts cystathione into cysteine.
Deficiencies in any of the following:
-tetrahydrofolate
-Vit B6
Vit B12
leads to….?
Homocysteinemia
Cystathionine synthase deficiency is also called…
Homocysteinemia
How do you treat homocysteinemia?
Reduction of Homocysteine and Met from the blood.
Low Met diet
HIGH DOSE OF VIT B6
To make Tyr from Phe, what cofactor does the hydroxylase enzyme require?
BH4, tetrahydrofolate
Deficiency of Phenylalanine Hydroxylase leads to what disease? (catalyzes Phe-> Tyr)
PKU - as Phe accumulates, Phenyl ketones are excreted
Tyrosine is a precursor for what?
Melanin
Thyroid hormones
Neurotransmitters
Describe some symptoms of PKU. (think about what tyrosine does.)
Albinism or light tones (melanin) Mental retardation (neurotransmitters)
How do you try to treat PKU?
Diet rich in Tyr, Low in Phe
Semisynthetic Phe, special diets
Is tryptophan metabolism depended on PLP?
Yes
Trp deficiency presents itself with what kind of symptoms?
Pellagra-like. Niacin deficiency. 3 D’s. Diarrhea, etc…
What AA’s are involved with Maple Syrup Urine disease?
BRANCHED: Isoleucine, Valine, and Leucine
What enzyme is defective in Maple syrup Urine disease?
a-ketoacid dehydrogenase
HIstidine is a precursor to ….
Histamine- allergic response, vasodilator
True/False: HIstidine is an inhibitory neurotransmitter in the brain
False. It is an EXCITATORY neurotransmitter
WHat amino acid is creatine derived from?
Glycine!
If there is elevated CK in the blood plasma and none in the urine, what is indicated?
kidney malfunction. Plasma creatine is usually low because it is filtered out by the kidneys
Heme is synthesized from what AA?
Glycine
Glutamate is the precursor for what inhibitory neurotransmitter?
GABA
Glutamate, itself, is the most common neurotransmitter in the CNS. Is it excitatory or inhibitory?
Excitatory
Nitric Oxide (NO) is synthesized from what AA?
Arginine
NO initiates what messenger pathway?
Gyanylyl cyclase -> cGMP
TYROSINE is the precursor to 3 things. name them.
1- Melanin
2- Thyroid hormones (Thyroxine)
3- Catecholamines (NEUROTRANSMITTERS)
Serotonin and Melatonin are synthesized from what AA?
Tryptophan.
WHere is serotonin made and stored?
Made in GI tract, stored in platelets.
Serotonin is acetylated in the pineal gland of the brain to become…..
Melatonin
