8 AA metabolism 1 Flashcards
What are AA?
building blocks of proteins
How can AA be placed into 5 basic groups?
based on their R substituents
What are the 5 AA groups?
- non polar, aliphatic
- aromatic
- polar, uncharged
- pos charge
- neg charge
How can atmospheric N₂ be used by biological systems?
need to be converted to ammonia (NH3) first in a process called nitrogen fixation
Are higher organisms (i.e. humans) able to fix nitrogen?
no higher organisms are not capable of fixing nitrogen
what performs nitrogen fixation of atmospheric N₂?
some bacteria and archea
e.g. symbiotic rhizobium bacteria forms root nodules in which they fix nitrogen at the roots of legiminous plants to supply both the bacteria and the plants
What does assimilation of nitrogen into AA require?
requires the entry of ammonium ion (NH4+)
Which 2 synthesis of AA can assimilate nitrogen into AA?
glutamate and glutamine
the first NH₄+ is incorporated into glutamate
a second NH₄+ is incorporated into glutamate to form glutamine
so glutamine is basically glutamate with incorporation of 2 ammonium ion (NH₄+)
How can other AA bio biosynthesized?
- start from glucose
- go down glycolytic pathway -> pyruvate -> TCA cycle
- along the way can take stuff and make AA
What are essential vs non essential AA?
essential - must be obtain from diet
rest are nonessential
9 are essential
How can aspartate and alanine be synthesized (nonessential)?
aspartate = glutamate + oxaloacetate (using AST = aspartate-aminotransferase)
alanine = glutamate + pyruvate (using ALT = alanine aminotransferase)
How can aparagine be synthesised?
like glutamine, addition of a second NH₄+ group to aspartate can yield asparagine
done by transferring the NH₄+ group from glutamine to aspartate
what is the intermediate and resulting AA of the starting carbohydrate/ketoacid α-ketoglutarate?
α-ketoglutarate
glutamate
glutamine, proline arginine
what is the intermediate and resulting AA of the starting carbohydrate/ketoacid 3-phosphoglycerate?
serine
glycine, cysteine
How is glycine synthesised?
from serine via losing the side chain methylene group
it doesnt have any side chains
its a long process
