PROTEINS

Question 1

enzyme deficient in PKU

Answer 1

phenylalanine hydroxylase

Question 2

without PAH enzyme, what is the value of phenylalanine levels?

Answer 2

> 1,200 umol/L

Question 3

newborn upper limit for pku

Answer 3

120umol/L or 2mg/dL

Question 4

value of phenylalanine in untreated classic PKU

Answer 4

as high as 2.4 mM/L

Question 5

what are the metabolites of phenylalanine that may be present in urine sample of a px with PKU?

Answer 5

• phenylpyruvate or phenylketone
• phenylpyruvicacid
  -phenyllactic acid

Question 6

odor of urine in PKU?

Answer 6

musty odor

Question 7

phenylalanine levels of partial deficiencies of PAH or “mild pku”

Answer 7

600-1200 umol/L

Question 8

Non-PKU mild hyperphenylalaninemia

Answer 8

180-600 umol/L

Question 9

is a co – factor in the
enzymatic hydroxylation of phenylalanine, tryptophan and tyrosine

Answer 9

tetrahydrobiopterin

Question 10

a non-protein chemical/entity that
must bind to a particular enzyme before
reaction occurs

Answer 10

co-factor

Question 11

goal of pku treatment

Answer 11

maintain blood level of phenylalanine (2-10 mg/dL or 120- 160 μmol/L)

Question 12

first drug to manage pku?

Answer 12

kuvan (sapropterin dihydrochloride)

Question 13

action of kuvan?

Answer 13

helps reduce the phenylalanine levels by increasing the activity of PAH enzyme

Question 14

color of urine in ferric chloride tube test for PKU

Answer 14

permanent blue green color

Question 15

sensitivity of Guthrie Inhibition Test for PKU

Answer 15

180-240 umol/L

Question 16

inhibitor of B. subtilis in PKU

Answer 16

B2-thienlyalanine

Question 17

Describes the ability of phenylalanine to facilitate bacterial growth in a culture medium even under the presence of inhibitor

Answer 17

Guthrie Test or Guthrie Inhibition Assay

Question 18

• Direct measurement of phenylalanine in dried blood filter disks; quantitative
• Principle: It is based on the fluorescence of a complex formed of phenylalanine– ninhydrin–copper in the presence of a dipeptide.

Answer 18

microfluorometric assay

Question 19

wavelengths at which the fluorescence is measured in the microfluorometric assay for PKU

Answer 19

360 nm and 530 nm

Question 20

wavelengths at which the fluorescence is measured in the microfluorometric assay for PKU

Answer 20

360 nm and 530m,

Question 21

Reference method for quantitative serum phenylalanine

Answer 21

HPLC

Question 22

Used in screening for inherited disorders in newborns

Answer 22

ms/ms

Question 23

Amino acids are extracted from neonatal blood
samples and rapidly derived with N,Obis (trimethylsilyl)-trifluoroacetamide under microwave irradiation.

Answer 23

Microwave-assisted silylation followed by gas chromatography–mass spectrometry (GC/MS):

Question 24

what is the purpose of silylation?

Answer 24

to increase the stability of the analyte and improve the gas chromatography behavior

Question 25

silylating agent used in Microwave-assisted silylation followed by gas chromatography–mass spectrometry (GC/MS):

Answer 25

N,Obis(trimethylsilyl)-trifluoroacetamide

Question 26

characterized by the excretion of tyrosine and tyrosine catabolites in urine

Answer 26

tyrosinemia

Question 27

give the enzymes deficient in the 3 types of Tyrosinemia

Answer 27

Type 1: fumarylacetoacetate hydrolase
Type 2: tyrosine aminotransferase
Type 3: 4-hydroxyphenylpyruvate dioxygenase

Question 28

diagnostic criteria for tyrosinemia?

Answer 28

• increased tyrosine level detected using ms/ms
• confirmatory test for elevated level of succinylacetone

Question 29

color of urine sample in ferric chloride tube test for tyrosinemia

Answer 29

transient green color

Question 30

color of urine sample in nitroso-naphthol test for tyrosinemia?

Answer 30

orange red color

Question 31

drug treatment for tyrosinemia

Answer 31

nitisinone

Question 32

action of nitisinone as a drug treatment for tyrosinemia?

Answer 32

Prevents the formation of malylacetoacetic acid
and fumarylacetoacetic acid which can be
converted to succinylacetone

Question 33

treatment for tyrosinemia?

Answer 33

• low protein diet
• nitisione
• partial or full liver transplant

Question 34

• most severe form of tyrosinemia
• Failure to thrive, diarrhea, vomiting, jaundice, cabbage-like odor, distended abdomen, swelling
  of legs, and increased predisposition for bleeding
• Can lead to liver and kidney failure, nervous system problems, and an increased risk of cirrhosis or liver cancer later in life

Answer 34

type 1

Question 35

• tyrosinemia that occurs in 1 in every 250,000 births
• Mental retardation and have symptoms of
  excessive tearing, photophobia, eye pain and redness, and painful skin lesions on the palms and soles of the feet

Answer 35

type II

Question 36

Mild mental retardation, seizures, and periodic
loss of balance and coordination

Answer 36

type III tyrosinemia

Question 37

enzyme deficient in alkaptonuria?

Answer 37

homogentisate oxidase

Question 38

Significant manifestation of alkaptonuria

Answer 38

Patient’s urine turns brownish-black when it mixes with air

Question 39

indicate the color manifested in urine sample for the ff tests for alkaptonuria:

• Ferric chloride tube test
• Clinitest
• Homogentisic acid test

Answer 39

• Ferric chloride tube test - deep blue (Strasinger) / black (Bishop)
• Clinitest - yellow precipitate
• Homogentisic acid test - black

Question 40

treatment for alkaptonuria?

Answer 40

high dose of vitamin C

Question 41

enzyme deficient in MSUD?

Answer 41

a-ketoacid decarboxylase

Question 42

odor of urine in msud?

Answer 42

maple syrup or burnt sugar odor of urine

Question 43

in msud, what are the 3 branched-chain amino acids whose metabolism is blocked?

Answer 43

leucine
isoleucine
valine