Amino Acids

• Amino acids are the monomeric building blocks from which proteins are constructed
• There are 20 different amino acids which are universal to all living organisms
• Amino acids can be essential, non-essential, or conditionally non-essential according to dietary requirements
• Essential amino acids cannot be produced by the body and must be present in the diet
• Non-essential amino acids can be produced by the body and are not required as part of the diet
• Conditionally non-essential amino acids can be produced by the body, but at rates lower than certain conditional requirements - they are essential at certain times only
• A shortage of essential amino acids in the diet will prevent the production of specific proteins, leading to protein deficiency malnutrition
• Phenylketonuria (PKU) is a genetic condition that impairs the metabolism of the amino acid phenylalanine
• PKU is an autosomal recessive disorder caused by a mutation to the gene encoding the enzyme phenylalanine hydroxylase
• In PKU, excess phenylalanine is converted into phenylpyruvate, leading to a toxic build-up of phenylketone in the blood and urine
• Untreated PKU can result in brain damage, mental retardation, and other serious medical problems
• Diagnosis of PKU is made by a blood test for elevated phenylalanine levels shortly after birth as infants are normal at birth due to their mother's ability to break down phenylalanine during pregnancy
• PKU is treated by enforcing a strict diet that restricts the intake of phenylalanine to prevent its build-up in the body
• Phenylalanine hydroxylase normally converts excess phenylalanine within the body into tyrosine
• A PKU diet is low-protein and is supplemented with a medical formula that contains precise quantities of essential amino acids
• If PKU is caught early and treated consistently, the patient can live a normal life
• Essential vs. Non-essential amino acids