Nitrogen Flashcards
What is transamination?
Transferring amino groups between different molecules
What are the main nitrogen containing molecules in the body?
Amino acids and nucleotides
-Glutamate, glutanin, aspartate, alanine
Principles of transamination
- No loss or gain of nitrogen
- Readily reversible therefore transaminases participate in AA synthesis and deviation
What are aminotransferases reliant on?
Pyridoxal phosphates (PLP) cofactor - made from vitamin B
Tranfers AA groups during reaction
What alpha-veto acid accept amino groups?
a-ketoglutarate
What acts as a temporary storage of nitrogen?
Glutamine - can donate the amino group when required for AA biosynthesis
What can the presence of aminotransferases indicate?
Prescene in plasma indicates cell damage - high ALT or AST can indicate liver disease
Function of aspartate aminotransferase (AST)?
Catalyse aspartate to oxaloacetate
Function of alanine amino aminotransferase (ALT)?
Catalyse alanine to pyruvate
What does the oxidation of AA produce?
Lots of energy - 90% of energy requirements fuelled by AA in carnivores
Little energy in herbivores
What 3 circumstanced to AA undergo oxidative catabolism?
- Left over AA
- Dietary AA exceed body’s protein synthesis
- Protein in body that are broken down to supply AA for catabolism when carbs are in short (starvation, diabetes)
Function of Trypsin and chymotrypsin
cut protein and larger peptides into smaller peptide in the small intestine
Function of pepsin
cuts proteins into peptides in the stomach
Function of Aminopeptidase and carboxypeptidases A and B
degrade peptide into amino acids in the small intestine
What process supply AA for digestion?
Digestion of dietary proteins and degradation of proteins in cells
