AMINOACIDOPATHIES Flashcards by Kyla Keim Insular

Rare, inherited disorders of amino acid metabolism

AMINOACIDOPATHIES

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2 abnormalities in AMINOACIDOPATHIES

Specific enzyme (defect or deficiency) in metabolic pathway or membrane transport system

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PHENYLKETONURIA (PKU) is the Total absence of activity of ___

PHENYLALANINE HYDROXYLASE

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PHENYLALANINE HYDROXYLASE catalyzes the conversion of
phenylalanine to ___

tyrosine

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There is an accumulation of levels of Phenylalanine and its metabolites (eg. phenylpyruvic acid, phenylpyruvate also known as phenylketone, and phenylacetic

PHENYLKETONURIA (PKU)

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Increase of Phenylalanine on the blood

Hyperphenylalaninemia

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There is a presence of Phenylalanine in the Urine

Phenylketonuria

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The presence of Phe in urine happens because it surpases the amount of proteins or metabolites that the kidney can filter or what we call ___

Renal Threshold

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Phenylketonuria causes the urine to have a characteristic ___ odor.

“musty” or “mousy”

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Complications in infants and children with Phenylketonuria

retarded mental development and microcephaly

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Fetal effects of maternal PKU are preventable
if the mother maintains a ___ before conception and throughout pregnancy.

phenylalanine-restricted diet

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Metabolites of Phenylalanine

Phenylpyruvate, Phenylacetic acid, Phenylacetylglutamine

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is derived from the deamination of phenylalanine

Phenylpyruvate

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Decarboxylation and Oxidation of Phenylpyruvate

Phenylacetic acid

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Occurs as a result of the toxic effects of the brain of phenylpyruvate or
one of its metabolic by-products

Retarded mental development

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Retarded mental development occurs in what week of life

2nd or 3rd week of life

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glutamine conjugate of phenylacetate

Phenylacetylglutamine

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a semiquantitative, bacterial inhibition assay for phenylalanine based on the ability of phenylalanine to facilitate bacterial growth in a culture medium despite the presence of a growth inhibitor.

Guthrie Bacterial Inhibition Assay

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in Guthrie Bacterial Inhibition Assay, spores of __ are incorporated into an agar plate that contains ___ (antagonist or inhibitor)

Bacillus subtilis; beta-2- thienylalanine

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If blood phenylalanine exceeds
___ mg/dL, phenylalanine
counteracts the antagonist
and bacterial growth occurs

3-4

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In Guthrie Bacterial Inhibition
Assay:
Presence of Bacterial Halo = __
Absence of Bacterial Halo = __

Positive
Negative

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direct measurement of
phenylalanine in dried blood
filter disks

Microfluorometric assay

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Microfluorometric assay in phenylketonuria is based on the ___ of a
complex formed of
___ in
the presence of a dipeptide ___

fluorescence; phenylalanine-ninhydrin-copper; Lleucyl-L-alanine

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in Microfluorometric assay in phenylketonuria:
Excitation wavelengths = ___
emission wavelengths = ___

360 nm
530 nm

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Microfluorometric assay in Phenylketonuria requires pretreatment of the dried blood filter disk with ___

trichloroacetic acid (TCA)

The reference method or standard method for detecting PKU

High-Performance Liquid Chromatography (HPLC)

In High-Performance Liquid Chromatography (HPLC), phenylketonuria is detected in newborn's blood in ___ mg/dL

1.2 -3.4 mg/dl (70/200 umol/L)

in Microfluorometric Assay, the microtiter plate is made of a mixture of ___, ____, ___ in the presence of ___.

ninhydrin, succinate, and leucylalanine; copper tartrate

Used for Monitoring in phenylketonuria and a Reagent Strip Test

Urine Test

Urine Test involves the reaction of ___ with __ in urine to produce a ___ color

ferric chloride; phenylpyruvic acid; green

Characterized by excretion of tyrosine and tyrosine catabolites in urine

TYROSINEMIA

is the most severe form of TYROSINEMIA

Type I Tyrosinemia

a type of Tyrosinemia which symptoms are failure to thrive, diarrhea, vomiting, jaundice, a cabbage-like odor, distended abdomen, swelling of the legs, and an increased predisposition for bleeding.

Type I Tyrosinemia

complications of tyrosinemia

Leads to liver damage (Cirrhosis and liver cancer)

type 3 tyrosinemia enzyme deficiency

4-hydroxy-phenylpyruvic acid oxidase

type 1 tyrosinemia enzyme deficiency

Fumarylacetoacetate (FAA) hydrolase

type 2 tyrosinemia enzyme deficiency

tyrosine aminotransferase

ALKAPTONURIA is the lack of ___

homogentisate oxidase

homogentisic acid (HGA) accumulates in connective tissue causing generalized pigmentation of these tissues called ___, an arthritis-like degeneration

Ochronosis

Accumulation of homogentisic acid (HGA) is characterized by ___ of urine

darkening

2 clinical manifestations of alkaptonuria

ochronosis and darkening of urine

Familial inheritance aminoacidopathy

ALKAPTONURIA

elevated concentrations of homogentisic acid (HGA) in the blood

alkaptonuria

Characterized by burnt sugar odor of the urine, breath, and skin

MAPLE SYRUP URINE DISEASE

MAPLE SYRUP URINE DISEASE lacks the enzyme ___

branched-chain alpha-ketoacid decarboxylase

alpha-ketoacid decarboxylase blocks the normal metabolism of

Leucine, Isoleucine and Valine

COMPLICATIONS: Lethargy, failure to thrive, Muscle rigidity, Respiratory irregularities, Mental retardation, Convulsions, Acidosis and hypoglycemia

MAPLE SYRUP URINE DISEASE

in Microfluorometric assay in MAPLE SYRUP URINE DISEASE, pretreatment used are

solvent mixture of methanol and acetone

in Microfluorometric assay in MAPLE SYRUP URINE DISEASE, extract used is

Leucine dehydrogenase

in Microfluorometric Assay in Maple Syrup Disease: excitation wavelength = ___ emission wavelength = ___

360 nm 450 nm

above __ mg/dL is indicative of MAPLE SYRUP URINE DISEASE

ISOVALERIC ACIDEMIA is the deficiency of ___ in leucine pathway

isovaleryl-CoA dehydrogenase

odor of urine in ISOVALERIC ACIDEMIA

sweaty feet

in HOMOCYSTINURIA, there is an increase in ___

homocysteine

Intermediate amino acid in the synthesis of cysteine from methionine

Homocysteine

In homocystinuria, there is an impaired activity of ___ which converts homocysteine to ___

cystathionine beta-synthase; cysteine

– Cysteine and homocysteine are reduced by sodium cyanide to free-thiol – Then, reacted to sodium nitroprusside to produce a ___color

Cyanide-Nitroprusside Urine Spot Test; red-purple

Confirmation for homocysteine * Silver nitrate reduces homocysteine to form __ color

Silver-nitroprusside Test; reddish

COMPLICATIONS: – Thromboembolism, Cardiovascular risk, Atherosclerotic disease, Low folate concentrations, Vitamin B12 deficiency

HOMOCYSTINURIA

2 diseases that results from inherited enzyme deficiencies in the urea cycle

CITRULLINEMIA and ARGININOSUCCINIC ACIDURIA

TYPE 1 CITRULLINEMIA lacks the enzyme ___

argininosuccinic acid synthetase (ASS)

complications of citrullinemia

Vomiting, high ammonia levels and Mental retardation

caused by a mutation of the gene that would provide instructions for making the protein citrin

TYPE 2 CITRULLINEMIA

lack of __ inhibits the urea cycle and disrupts the production of proteins and nucleotides and this happens in what type of disease?

citrin; Type II Citrullinemia

in Type I Citrullinemia, there is an increase in ___ and it will not be converted to ___

citrulline; arginosuccinic acid

The resulting accumulation of ___ and other toxic substances in citrullinemia leads to confusion, restlessness, memory loss, personality changes, seizures, and coma

ammonia

deficiency in argininosuccinate lyase (ASL) prevents the conversion of argininosuccinic acid into ___

arginine

in ARGININOSUCCINIC ACIDURIA, there is deficiency in ___

argininosuccinate lyase (ASL)

a defect in the amino acid transport system rather than a metabolic enzyme deficiency

CYSTINURIA

ARGININOSUCCINIC ACIDURIA complications

Vomiting, high ammonia levels and Mental retardation

in ARGININOSUCCINIC ACIDURIA, there is accumulation of __

argininosuccinate

in cystinuria, there is Increased urinary excretion of ___

cystine

Increased urinary excretion of cystine resulting from genetic defect in the ___

renal resorptive mechanism

Cystine is insoluble and tends to precipitate in the kidney tubules and cause ___

URINARY CALCULI or kidney stones