WEEK 8 (Amino acid metabolism) Flashcards
What are amino acids?
Amino acids are organic compounds containing an AMINE GROUP, CARBOXYL GROUP, VARIABLE GROUP and a H ATOM around a central carbon atom
What are the major key elements of amino acids?
- Carbon
- Hydrogen
- Nitrogen
- Oxygen
Which amino acids are non-polar?
- Glycine
- Alanine
- Proline
- Valine
- Leucine
- Isoleucine
- Methionine
- Tryptophan
- Phenylalanine
Which amino acids are polar and uncharged?
- Cysteine
- Asparagine
- Glutamine
- Serine
- Threonine
- Tyrosine
Which amino acids are charged?
- Histidine
- Arginine
- Lysine
- Aspartate
- Glutamate
What is the difference between Essential amino acids and Non-essential amino acids?
ESSENTIAL AMINO ACIDS = cannot be synthesised by the body -> must be consumed
NONESSENTIAL AMINO ACIDS = can be synthesised
Which amino acids are essential?
- Leucine (KETOGENIC)
- Lysine (KETOGENIC)
- Phenylalanine (KETOGENIC/GLUCOGENIC)
- Isoleucine (KETOGENIC/GLUCOGENIC)
- Threonine (KETOGENIC/GLUCOGENIC)
- Tryptophan (KETOGENIC/GLUCOGENIC)
- Methionine (GLUCOGENIC)
- Valine (GLUCOGENIC)
- Arginine (GLUCOGENIC)
- Histidine (GLUCOGENIC)
Which amino acids are nonessential?
- Alanine (GLUCOGENIC)
- Asparagine (GLUCOGENIC)
- Aspartate (GLUCOGENIC)
- Glutamate (GLUCOGENIC)
- Glutamine (GLUCOGENIC)
- Glycine (GLUCOGENIC)
- Proline (GLUCOGENIC)
- Serine (GLUCOGENIC)
- Cysteine (GLUCOGENIC)
- Tyrosine (KETOGENIC/GLUCOGENIC)
What differentiates amino acids and proteins from fats and carbohydrates?
Unlike fats and carbohydrates, there is no storage form of amino acids and proteins so any excess/unused amino acids are broken down
What happens in amino acid breakdown?
The amino group is removed forming NH3 + ALPHA-KETO ACID
What are the properties of ammonia?
- Toxic to the body
- Needs to be transferred to LIVER in a NON-TOXIC STRUCTURE
- Converted by liver to UREA (non-toxic) for excretion by kidneys
All amino acids except ________ and _________ participate in transamination at some point in their catabolism
Lysine and Threonine
What are aminotransferases?
Transfer nitrogen from amino acids to glutamate
What do all aminotransferases require?
The prosthetic group PYRIDOXAL PHOSPHATE (PLP) which is derived from PYRIDOXINE (VITAMIN B6)
What is the clinical significance of Aminotransferases?
Aminotransferases are INTRACELLULAR ENZYMES with LOW LEVELS found in the plasma -> represents release of cellular contents during normal cell turnover -> ELEVATED PLASMA LEVELS of aminotransferases indicate DAMAGE to cells rich in these enzymes