Amino acid synthesis Flashcards
What does glyphosphate do?
Prevents plants from making certain amino acids essential for growth
What are amino acids made of.
N: atmosphere is rich in N2. Microbes can convert N2 into NH4+ which can be used to make amino acids
C: carbon skeletons provided by intermediates of major metabolic pathways
What process makes ammonium?
Haber-Bosch process produces ammonia by using irn based catalustes at extreme temperatires
What nitrogen-fixing bacteria converts N2 into NH3 (a form that bacteria can use)? What enzyme?
diazotrophs
nitrogenase
The symbiotant relationship between plants and microbes. What do plants provide? what do rhizobium rpovide?
Plants make o2 levcels low by providing leghemoglobin.
provide c4 intermeidates of the TCA (succinate, fumarate, malata) -> used as energy by microbes.
Rhibozium fixes the N in the form of ammonia which plants can use.
What is the nitrogenase complex?
Nitrogenase consists of 2 proteins: a reductase which provides elecctrons with high reducing power and a nitrogenase which uses these electrons to reduce N2 to NH2.
Transfer of electrons from reductase to nitrogenase requires hydrolysis of ATP.
Electrons flow from ferredoxin to the reductase (Fe protein) to nitrogenase (MoFe proten) to redudce nitrogen to ammonia.
How much ATP are hydrolyzed for each molecule of N2 reduced?
16.
Does the nitrogenase require oxygen?
Nitrogenase is inactivated by O2. But it needs oxidative phosphorylation to generate ATP to fuel N fixation
What is the conflict of interest in oxygen?
O2 inactivates nitrogenase, but plants need energy
-> compromise. leguminous plants maintain a very low cncentration of free O2 by binding O2 to leghemoglobin produced by host plant.
How is ammonium incorporated into glutamate and glutamine?
alpha keto glutarate and glutamate accept NH4 and form glutamate and glutamine resepectively.
Glutamate is a common amino group donor to various alpha keto acids -> form most of the amino acids by transamination.
Where do the amino acid carbon skeletons come from?
The intermediates of glycolysis
TCA
Pentose phosphate pathway
What are the 3 families of amino acids
- Aromatic amino acids
- Asparate (OAA) derived amino acids
- Branched chain amino acids
What are the different ways amino acids can be regulated?
Feedback inhibition
Enzyme multiplity (isoenzymes): the commited step is catalyzed by 2 or more enzymes with different regulatory properties
What is the shikimate pathway?
syntehsize chorismate -> precursor for Tryptophan, phenylanaline, tyropsine. -> precursosrs for othenr amino acids
How is chromisate partitioned.
Spilited between Tryptophan, phenyl alanine and tyrosine.
Typtophan is a positive regualtor for chromisate mutase -> increases the production of phenylanaine and tyrosine.
Phenylananine and tyrosine and negative inhibitos whihc conouteracts the activation from tryptophan
Whats the idea gained from the chromisate partitioning?
A product is increasing -> can be used to negatively regulate the enzyme thats creating it. and be a positive regulator for another enzyme that increases other products
How to study mutants in plants?
fluorescence at certain intermediates
