Nitrogen Flashcards
What is the main supplier of nitrogen?
Glutamine
What does Delta-ALA synthesise? Why is this important?
Heme. Heme forms haemoglobin which is important for oxygen transport
What forms Delta-ALA?
Glycine and Glutamine
What is the condition associated with inefficient Delta-ALA synthesis?
Porphyria
What is nitrogen used for in the body?
Synthesis of Delta-ALA
Biosynthesis of Creatine and Phosphocreatine
Glutathione (GSH) production
What is phosphocreatine used for?
Replenish ATP levels in the muscle tissue after exercise, it donates a phosphate which allows the conversion of ADP to ATP
What is GSH derived from? HINT: Tripeptide
Glutamate, Cysteine, Glycine
What are the two forms of GSH?
Reduced: GSH
Oxidised: GSSG
What does GSH do?
Protects us from oxidative stress
Keeps biological molecules in their reduced form
- e.g. haemoglobin: remains in Fe2+ from in order to bind to oxygen, Fe3+ form cannot bind
What are the repercussions of oxidative stress?
Aging, disease, apoptosis
What can the ratio of GSSG: GSH be used as?
A biomarker for oxidative stress
How is GSSG formed?
When a disulphide bridge forms between two oxidised cysteine amino acids, that then become known as cystine molecules
What causes oxidative damage?
When oxygen is oxidised to superoxide radical, hydrogen peroxide and hydroxyl free radical- these are highly toxic compounds that can damage cell contents and cause oxidative damage
Where does oxidative damage occur?
Lipids (rancidity)
Proteins (alters structure which impacts function)
DNA (mutations)
How are we protected against oxidative damage? What mediates this process?
Mediated by GSH
Converting GSSG to GSH, by glutathione reductase, protects us from oxidative stress
Which amino acid is a precursor for nitric oxide?
Arginine
What is nitric oxide?
A vasodilator
Where is nitrogen found?
In nucleic acids and amino acids
Does nitrogen require a high or low activation energy?
High- due to the triple bond between the two nitrogen molecules, makes it difficult to break
What is an example of a nitrogen fixing microorganism?
Archea
Can live in symbiosis with plants or animals
What is the nitrogenous complex?
N2 + 3H2 —–> 2NH3
What is the nitrogen cycle?
Where nitrogen fixing bacteria and archea convert atmospheric nitrogen to ammonia, which is then used to make amino acids
Does nitrogen fixation by the nitrogenous complex have a high or low energy demand?
High- requires 16 ATP and electrons
What is the equation for ammonia assimilation into glutamate?
What enzyme catalyses this reaction?
NH4 + alpha-ketoglutarate + NADPH –>/
How is glutamine produced?
By adding another ammonia to glutamate
What is the most common free amino acid in the blood and what is its role?
Glutamine
Role: to apply nitrogen to reactions around the body, without the need for ammonia
What are the 3 types of amino acid?
Non-essential
Conditionally essential
Essential
What is the purpose of protein turnover?
To recycle proteins within the body
What is the role of nitrogen flow? What enzyme is this reaction catalysed by?
To prevent free ammonia being present in the blood.
Catalysed by glutamate dehydrogenase
What is the role of the alanine cycle?
To prevent the formation of lactic acid
