Amino Acids as precursors Flashcards
what are AA used for
gluconeogenesis, protein building blocks
what is the AA that serves directly as a neurotransmitter?
explain
glycine
Functions directly as a neurotransmitter- acts to block impulses traveling in the spinal cord to stimulate skeletal muscle
Glycine is also a precursor for what
clycocholic acid (bile salt)
It is conjugated to cholesterol derivative to form glycocholic acid (bile salt)
biochemist’s simple definiton of neurotransmitter ( 4 things)
Molecule that is synthesized and stored in synaptic vesicles in neural cells
Release is triggered by an action potential
Bound & recognized by target cell
Activity can be regulated
which nucleic base is synthesized de novo using glycine
purines
what does glycine condenses with in the first step of heme biosynthesis
what is end product?
succinyl CoA
(protoporphyrin IX + Iron) to make heme
what are the 2 predominant circulation AA’s
Along with glutamine, a predominant circulating amino acid
what does Alanine do?
what reaction is involved?
what is the name of the relevant cycle?
Transports amino groups from muscle to liver (transamination from muscle pyruvate) in a process called the glucose-alanine cycle
what is Serine used for?
Source of one-carbon fragments (folate derivatives) used in biosynthesis
one carbon fragments with folate is used are 1 C building blocks
many steps require addition of 1 carbon units
tetrahydrofolate is vitamin cofactor
describe glucose alanine cycle
glucose broken down to pyruvate
reacted with glutamate via alanine aminotransferase to make alpha-ketogluterate and alanine
carried in blood to liver
alanine reacts with alpha ketogluterate to remake glutamate and pyruvate using same enzyme ( alanine aminotransferase)
pyruvate used to regenerate glucose through gluconeogenesis
Glutamate releases NH4+ in liver with goes through urea cycle and is excreted as urea
glutamine is used for what
serves as amino transporter like alanine
source of NH4+ in kidney
what else is glutamine involved in
Amino group donor in purine biosynthesis
Amino group donor in biosynthesis of amino sugars
what is the key rxn of amino sugar synthesis
Fructose-6-P + glutamine —>
Glucosamine-6-P + glutamate
-all amino sugars are then derived from Glucosamine-6-P
glutamate is used for what
- primary Neurotransmitter in CNS (flavor enhancer)
- acts on both ion channels and G coupled receptors
- in food as MSG
where are aminosugars found?
extracellular matrix and certain connective tissues
how is glutamate made into GABA? name enzyme and cofactor used
what is GABA receptor a target for?
glutamate a source of gamma amino butyrate (GABA) via decarboxylation of the alpha-carboxyl.
Enzyme: glutamate decarboxylase and PLPcofactor
GABA is the major inhibitory transmitter in the brain;
- the GABA receptor is the target of benzodiazepines/ barbiturates
glutamate also participates in what reaction involving amino groups
-transaminations: glutamate is the source of amino groups for most other amino acids
-donates n terminus amine group to form alpha ketogluterate ; converting alpha keto acid to L-amino acid (generic)
Enzyme: aminotransferase
- Pyridoxal phosphate (PLP) is cofactor
PLP is cofactor in what types of reactions
decarboxylations and transaminations
gluatamate is converted to glutamine via what
- ammonia fixation
- glutamate + NH4 + + ATP –> glutamine + ADP + Pi + H+
minor pathway that makes glutamate and fixates ammonium ion
NH4 + alpha-ketogluterate –> glutamate + H2O
enzyme: glutamate dehydrogenase
methionine reacts with ATP to form what
S-adenosyl methionine (SAM)- source of methyl groups for most methylation reactions
SAM can be decarboxylated to leave
what cofactor used?
a propylamine residue attached to the sulfur - precursor of spermine and spermidine (“polyamines”)
PLP used
decarboxylated adoMet reacts with what enzymes
what is made ultimately
either propylaminotransferase I: or II to make polyamines
- polyamines are made: spermidine and spermine
what charge do polyamines have?
what does this help with
- positively charge amine groups
- helps with binding of nucleic acids
