Synthesis of amino acids and their derivatives Flashcards
All AA can be derived from
Intermediates of metabolic pathways
All AAs can be synthesized only in
Bacteria and plants
How many AAs mammals can synthesize
10
How many essential amino acids are there
9
Source of amino group for AAs synthesize
Glutamate and Glutamine
Name essential amino acids
Hisitidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
How to remember essential amino acids
Veterinarian Prescribed High Lipid Meal To Increase Triglyceride Levels
What are conditionally essential amino acids
We have the enzymatic machinery for their synthesize, but it is not efficient when it is not functioning (starvation, fever, young mammals)
What are non-standard AAs
Non protein coding , they are not used for protein synthesize
Selenocysteine
Pyrrolysine- found in bacteria
Selenocysteine used for
GABA (neurotransmitter)
Homocysteine
Glutathione Peroxidase -enzyme for elimination of oxidative stress
Where is selenocysteine synthesized and by what codon is coded
Synthesized on tRNA
UGA codes for this AA or stop codon depending on the context
What is the other way to categorize AAs except how they contribute to TCA cycle
What substances are used to synthesize AAs
Alpha- ketogluterate AAs (TCA cycle)
3-phosphoglycerate (glycolysis )
Oxaloacetate (TCA cycle)
Pyruvate
from alpha-ketogluterate what AAs can be synthesized
Glutamate and 3 more
from 3-phosphoglycerate what AAs can be synthesized
serine and 2 more
from oxaloacetate what AAs can be synthesized
Aspartate and 4 more
from pyruvate what AAs can be synthesized
Alanine
Phosphoenolpyruvate can be used for synthesize of AAs, but what is the problem
This machinery is present only in bacteria
What is special about synthesize of tyrosine
Mammals have a system that can convert phenyalalnine to tyrosine, not though erythrose 4-phosphate
So tyrosine can be essential, can be non-essential
From glutamate, what AAs can be obtained and their name
Glutamine
Proline
Arginine
As they can be made -> conditionally essential
From 3-phosphoglycerate you can get serine, which is not essential. What conditional essential can you get from serine
GLycine
Cysteine
What AAs oxaloacetate and pyruvate yield in mammals
Aspartate->Asparagine
Alanine respectively
Why synthesize of asparagine from aspartate is very importnant
Some of the cancer cells heavily dependent , so if you can synthesize an inhibitor for enzyme that converts aspartate to asparagine , thre is a treatment
Pentose phosphate pathway is not important for
AA synthesis in mammals
Heme is synthesized from ___ in mammals and from ___ in plants and most bacteria
Glycine
glutamate
What is the first step of glycine conversion
Converting Glycine to gamma-Aminolevulinate
What happens in second step of heme formation
8 gamma-aminolevulinate are put together in the ring structure protoporphyrin with the intermediate of porphobilinogen
How do we get heme from protoporphyrin
iron ion is added
Abnormal accumulation of porphyrin intermediates is called
Porphria diseases
How heme is used
Bile use and sometimes excreted through bile when RBCs die apart form oxygen carrying capacity
How heme is metabolized
Heme->biliverdin with heme oxygenase
Biliverdin->bilirubin with bilirubin reductase
How bilirubin in blood is metabolized
Bilirubin is transported to the liver where with glucuronyl-bilirubin tranferase it is converted to bilirubin diglucuronide intermediate, which is ultimately converted to bilirubin used for bile
What happens with bilirubin in bile
Bacteria converts it to urobilinogen. It is converted to urobilin-> transport in kidney-> amber color of the urine
Some urobilinogen is converted to stercobilin with the action of bacteria and excreted with feces
Disease that is caused by accumulation of bilirubin in circulation and how do we get it
Jaundice
It is showing in cornea, mucous membranes, etc.
adult-problems with liver, infants- liver has to mature, nothing to worry about
What helps with bilirubin metabolism
sunlight
How do we get bruises
from metabolism of heme, RBCs die and release red heme
And within few hours oxygen converts heme from red to blue
And then this heme is slowly metabolized to biliverdin-> green color and then ultimetely to bilirubin-yellow color
Creatine is synthesized from
Glycine, Arginine and Methione
What does creatine kinase do
phosphorylates creatine to phosphocreatine
why phosphocreatine is important
Plays a role in ATP synthesize , because it stores phosphate group for ATP synthesize (buffer for muscular ATP)
Glutathione is synthesized from
Glutamate
Cysteine
Glycine
Glytathione is the major
Antioxidant- prevents oxidative damage
What enzymes oxidizes glutathione to its oxidized form
Glutathione peroxidase
Neurotransmotters from AA ( exact names and functions of this neurotransmitters)
epinephrine (Flight or fight response) from tyrosine
GABA (inhibitory neurotransmitter in the central nervous system, needed for muscle tone) from glutamate
Histamine (released during allergic reactions, stimulates HCL secretion in the stomach) from histidine-essential
Serotonin (regulates intestinal movement and feel-good hormone) from tryptophan
Nucleotides are important for
Precursors of nucleic acids
Carriers of energy (ATP and GTP)
Components of cofactors (NAD,FAD,CoA)
Initiators of glycoenogenesis
Second messenger
The difference between nucleoside, nucleotide, nucleic acid
Nucleotide=Nucleoside+phosphate
Nucleoside=Pentose sugar+nitrogenous base
Nucleotides polymer chain= nucleic acid
Difference between purines and pyrimidines
Purines- two carbon-nitrogen rings (Guanine, Adenine)
Pyrimidine - one carbon-nitrogen ring (Cytosine, Thymine, Uracil)
Two pathways for nucleotides synthesize and their short description
De novo pathway - synthesized from metabolic precursors (AA,ribose 5-phosphate, CO2 and NH3)
Salvage pathway- purine/pyrimidine bases released from degradation of nucleotides
Nitrogen bases are not synthesized ___
Independent molecules( you will never see only nitrogenous bases)
Purine rings are built up on
Ribose phosphate
Pyrimidine ring are first synthesized as ___ and then attached to ___
Orotate
Ribose phosphate
Nucleotide pools are kept ___, so it is needed ___
Low
Needed to continually synthesize them
Precursors of nucleotides synthesis and where are they coming from
PRPP (5-phosphoribosyl 1-pyrophosphate) from ribose-5 phosphate from PPP for sugar and phosphate
Multiple AAs for purines and pyrimidines
Aspartate for pyrimidines
Glycine for purines
Glutamine- amino group donor for both
Precursors of de novo synthesize
PRPP Glutamine Glycine Glutamine Aspartate
In this order for inosinate (IMP)
What can happen to IMP
It can be converted to AMP and GMP
Regulation of de novo synthesis of purines
Ultimate products GMP and AMP inhibit conversion from IMP or it can inhibit the conversion of PRPP to IMP
IMP can inhibit PRPP
What is overall inhibition and specific inhibition
Overall- the pathway to IMP is stopped
Specific-When the conversion of IMP to AMP is inhibited by AMP but not GMP or GMP is inhibited by GMP not AMP
De novo synthsize of pyrimidines
Aspartate is converted to Orotate with cytoplasmic carbamoyl phosphate II system
PRPP comes in orotate is attached ultimately leading to UTP or uridine-5-phosphate ( the first one to synthesize)
Only then UTP is converted to CTP (cytidine)
How ribonucleotides are converted to deoxyribonucleotides
Hydrogen atoms are required for reduction to “deoxy” form are donated by NADPH from PPP
OH is replaced with H at 2nd carbon of the ribose sugar
How do we get dTMP
From dCDP and dUMP
