noun
definition
An essential amino acid C9H11NO2 found in most animal proteins; it is essential for growth; the inability to metabolize it leads to phenylketonuria; it is a constituent of aspartame.
Examples of phenylalanine in a Sentence
It contains phenylalanine, which is an excellent natural pain blocker.
The baby is unable to make an enzyme, phenylalanine hydroxylase, which converts phenylalanine hydroxylase, which converts phenylalanine to tyrosine.
Phenylketonuria is a genetic disorder, which means, from birth, these persons cannot break down the amino acid phenylalanine.
The laboratory method used to detect high blood phenylalanine concentrations is tandem mass spectrometry.
Classical PKU is caused by a deficiency of the liver enzyme phenylalanine hydroxylase, which converts the amino acid phenylalanine to tyrosine.
Yes, the sweetening agents used in Senokot Hi-Fibre are aspartame (a source of phenylalanine) and saccharin sodium.
Phenylketonuria-A condition caused by a genetic error of the body's metabolism, characterized by the absence of phenylalanine hydroxylase (an enzyme that converts phenylalanine into tyrosine).
Phenylalanine accumulates in blood and seriously impairs early neuronal development.
Phenylketonuria (PKU)-A rare, inherited, metabolic disorder in which the enzyme necessary to break down and use phenylalanine, an amino acid necessary for normal growth and development, is lacking.
As a result, phenylalanine builds up in the body causing mental retardation and other neurological problems.
Tyrosine-An amino acid synthesized by the body from the essential amino acid phenylalanine.
Phenylketonuria (PKU) is a rare metabolic disorder caused by a deficiency in the production of the hepatic (liver) enzyme phenylalanine hydroxylase (PAH).
The primary symptom of untreated PKU, mental retardation, is the result of consuming foods that contain the amino acid phenylalanine, which is toxic to brain tissue.
This enzyme converts (metabolizes) the amino acid called phenylalanine into another amino acid, tyrosine.
Above normal levels of phenylalanine are toxic to the cells that make up the nervous system and cause irreversible abnormalities in brain structure and function in PKU patients.
Phenylalanine is a type of teratogen (any substance or organism that can cause birth defects in a developing fetus).
In untreated PKU patients, abnormally high phenylalanine levels in the blood and brain can produce nerve cells with deformed axons and dendrites and cause imperfections in the myelin sheath referred to as hypomyelination and demylenation.
Mutations in the PAH gene prevent the liver from producing adequate levels of the PAH enzyme needed to break down phenylalanine.
Physiologically, PKU patients show high levels of phenylalanine and low levels of tyrosine in the blood.
The primary diagnostic test for PKU is the measurement of phenylalanine levels in a drop of blood taken from the heel of a newborn baby's foot.
In this test, PKU is confirmed by the appearance of bacteria growing around high concentrations of phenylalanine in the blood spot.
If the initial PKU test produces a positive result, then follow-up tests are performed to confirm the diagnosis and to determine if the elevated phenylalanine levels may be caused by some medical condition other than PKU.
Treatment for PKU is recommended for babies that show a blood phenylalanine level of 7 to 10 mg/dL or higher for more than a few consecutive days.
Another, more accurate test procedure for PKU measures the ratio (comparison) of the amount of phenylalanine to the amount of tyrosine in the blood.
Large-scale studies have helped to clarify how various mutations affect the ability of patients to process phenylalanine.
Infants with PKU should be put on a specialized diet as soon as they are diagnosed to avoid progressive brain damage and other problems caused by an accumulation of phenylalanine in the body.
A PKU diet helps patients maintain very low blood levels of phenylalanine by restricting the intake of natural foods that contain this amino acid.
Phenylalanine is actually an essential amino acid.
Typical diets prescribed for PKU patients provide very small amounts of phenylalanine and higher quantities of other amino acids, including tyrosine.
The amount of allowable phenylalanine can be increased slightly as a child grows older.
Sugar-free foods, such as diet soda, which contain the artificial sweetener aspartame, are also prohibited foods for PKU patients because aspartame contains the amino acid phenylalanine.
Ideally, school-age children with PKU should be taught to assume responsibility for managing their diets, recording food intake, and for performing simple blood tests to monitor their phenylalanine levels.
Blood tests should be done in the early morning when phenylalanine levels are highest.
The amount of natural foods allowed in a diet can be adjusted to ensure that the level of phenylalanine in the blood is kept within a safe range-2 to 6 mg/dL before 12 years of age and 2 to 15 mg/dL for PKU patients over 12 years old.
One promising line of PKU research involves the synthesis (manufacturing) of a new type of enzyme that can break down phenylalanine in food consumed by the patient.
This medication would be taken orally and could prevent the absorption of digested phenylalanine into the patient's bloodstream.
They should ensure that phenylalanine blood levels are under control before conception and throughout pregnancy.
Women who are at risk of phenylketonuria (PKU) should not take aspartame because it can increase the amount of the amino acid phenylalanine, which can harm the developing baby.
For example, a small percentage of people must keep the phenylalanine that they take in at a very low level because of a disease called Phenylketonuria.
The trouble is that phenylalanine is a requirement for the body to synthesize tyrosine.
Several dangers of phenylalanine supplements should be noted, especially for people with a genetic disorder called phenylketonuria (PKU).
Phenylalanine is a naturally occurring essential amino acid.
The body converts phenylalanine into l-tyrosine, another amino acid, which is the precursor to brain chemicals include dopamine, norepinephrine and epinephrine.
Some people turn to phenylalanine supplements to regulate moods.
Like other amino acids, because phenylalanine is broken down into components used to create brain chemicals, the hope is that by taking supplements one can improve mood.
There's limited scientific research proving phenylalanine supplements work to boost mood, but many in the holistic or supplement industry believe they do and recommend them for this purpose.
Phenylalanine is of course dangerous to people with the inherited genetic condition called PKU, but it's also dangerous for people who have unrecognized mood disorders masquerading as depression.
Without proper diagnosis, such patients may try to self medicate using herbs or supplements such as phenylalanine.
Phenylketonuria is a genetically inherited disease in which people cannot process the amino acid phenylalanine.
The amino acid is either incompletely metabolized or improperly metabolized, with the resulting buildup of phenylalanine causing brain damage, mental retardation, or both.