MB unit 16: production of amino acids

21 flashcards · Other · by Yaiza Anido

1. What are essential amino acids? And name some of them

   An essential amin acid, is an amino acid that cannot be synthesized de novo (from scratch) by the organism, and thus must be supplied in its diet. Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine

2. What are 3 ways by which amino acids can be synthesized?

   Chemical synthesis: Since only the L form is used by cells it requires enzymatic transformation Protein hydrolisis mainly for histidine followed by a chromatographic separation Bacterial synthesis from nutreitns or precursors

3. What is required for the chemical synthesis of amino acids?

   Chemical syntehsis requires bacteria or trasnformation ny intracellular enzymes which is expensive. It may also sometimes required chemical intermediates

4. What is the role of the enzyme amino acid racemase in the chemical production of amino acids?

   Amino acid racemase is an enzyme that catalyzes the chemical reaction: L-amino acid ⇌ D-amino acid

5. What is the role of the enzyme Aminoacylase in the chemical production of amino acids?

   Aminoacylase is a hydrolase that produces L amino acids from N-acyl-L-aminoacids.

6. What can we use to increase L form amino acids from a D-L mix?

   A column containing aminoacylase

7. What are the amino acid producers deficient in?

   Amino acid producers are deficient in α-Ketoglutarate dehydrogenase.

8. How can we increase the amino acid byosynthesis yield?

   An increase in yield is achieved by affecting bacteria permeability.

9. what kind of m.o do we use for glutamate biosynthesis?

   Corynebacterium glutamicum A gram possitive rode shaped bacteria.

10. Explain the biosynthesis of glutamate with corynebacterium glutamicum

    For the biosynthesis of glutamate we use a fed batch culture system to form glutamic acid from glucose using C. glutamicum. For the source of Nitrogen we are going to feed the culture with Urea. The urea will also act as a pH buffer. The bioreactor will work at 28 celcius for 4 days. For the carbon source we are going to use Glucose. The primary metabolite will be glutamic acid. Other products may arise such as lactic acid but they are neutrized.

11. what does an accumulatin of alpha ketoglutarate adn glutamate dehydrogenase produce

    An accumulation of alpha ketoglutarate and glutamate dehydrogenase produces glutamate.

12. Explain the biosynthesis of glutamate with brevibacterium flavum

    We are going to use a fed batch culture system of glutamic acid from acetic acid. (first difference we can see in comparison to C.glutamicum) In this case our source of carbon will be acetic acid. The bioreactor will work for 4 days. Isocitrate lyase to produce Glioxylate cycle has a lower Km than isocytrate dehydrogenase. The subproducts that may arise are aspartic acid and alpha ketoglutarate.

13. What must happen to the glyoxylate pathway in order to accumulate alpha ketoglutarate.

    The Glyoxylate pathway must be saturated in order to accumulate alphaketoglutarate (delayed 1 day)

14. where can lysine be present?

    Lysine is present in leguminous cereals and vegetables.

15. what can lysine synthesis be afected by)

    The synthesis of lysine can be affect by the synthesis of other aa. If the percentage is bigger is becuase the enzyme works better.

16. What is a key factor to take into consideration when we have a pathway to produce a particular product in order to give the best yield.

    When we have a pathway and we have to produce a particular product we have to think the best way or mutants that would give the better yield.

17. When talking about the biosynthesis of aromatic aas, how do we need to start this process and from what does it start? What is the biosinthesis of aromatic amino acids subjected to?

    For the synthesis of aromatic aas we need to start upstrem in the glycolitic pathway. The synthesis of aromatic aas starts from eritrose-4-P and phosphoenolpyruvate. The biosynthesis of aromatic aas is subjected to retroibhibition

18. what kind of m.os can be used for tryptophan production?

    Different mutant strains and auxotrophic strains.

19. How is triptophan production by direct fermentation? How can we imporove production yield.

    Triptophan production by direct fermentation is low. To improve triptophan production yield we should add

20. What are 3 ways by which triptophan can be produced.

    Direct fermentation Using enzymes or inmobilized cells From precursors such as anthranilic acid and aspartate.