Unit 2 - Redone Flashcards
Humans contain combinations of how many amino acids for protein?
20 amino acids
How many amino acids are essential and cannot be synthesized?
9
What organs play a role in amino acid synthesis? What are the roles?
Liver and Kidneys
Transamination and deamination
Ampholyte
Ionized molecule with both negative and positive charges
Peptide bond
Bond between amino end of one a.a. and carboxyl end of next a.a.
Isoelectric point
pH where amino acid has no net charge
What determines an amino acid’s isoelectric point or pI?
R group
When a peptide bond forms, what releases?
Water
Which part of an amino acid is capable of donating hydrogen?
Amino group (NH3+)
Which part of amino acid is capable of accepting hydrogen?
Carboxyl group (COO-)
Why is water released from a peptide bond?
COOH gives up OH
NH2 gives up H
Oligopeptide
Short chain, up to 5 a.a.
Polypeptide
Chain of 6-30 a.a.
Proteins
Complex compounds with >40 a.a.
Proteome
Total array of proteins expressed by an organism’s genetic material under certain conditions
Aminoacidurias are either
Overflow or renal issues
Overflow
Blood/Plasma levels high
Renal threshold surpassed
Renal aminoacidurias
Blood/Plasma levels normal
Kidneys can’t reabsorb amino acid properly
Aminoacidopathies
Defect in handling parent amino acid (earlier in the line)
Organic acidemias
Defect in catabolic pathway (later down the line)
Normal phenylalanine handling
Phenylalanine + OH = Tyrosine
What is the main problem in PKU?
Virtually absent hydroxylase, can’t produce tyrosine
What is the product of PKU?
Instead of tyrosine, it’s toxic phenylpyruvate
What does toxic phenylpyruvate cause?
Failure to thrive in infants, can lead to irreversible retardation
What is the fix for PKU?
Avoid milk or aspartame
Take tyrosine
How is PKU identified?
Screening after sufficient milk feedings
OR
Mousy odor, blue-green color after addition of ferric chloride
When is PKU usually diagnosed?
Early on, at birth
What kind of amino acid issue is PKU?
Overflow, phenylalanine elevates in blood, CSF, urine
Tyrosine is a precursor for
Thyroid hormones
Adrenal hormones
Melanine
Tyrosinemia 1
Low fumarylactoacetate hydrolase
Near END of pathway
Tyrosinemia 2
Low tyrosine aminotransferase
Near START of pathway
Tyrosinemia 1 can cause
Failure to thrive
Liver/Spleen enlargement
Photophobia
Rickets
Liver disease/Cirrhosis
Tyrosine crystals in urine
Tyrosinemia 2 can cause
Issues with eyes, skin, brain
Alkaptonuria ususally diagnosed by
Urine blacken upon standing
Alkaptonuria occurs because of
Homogentisic acid low or missing
Why does urine darken in alkaptonuria
Alkaline urine, time/exposure to air
Diagnosis of alkaptonuria
HGA levels in blood
Quick confirmation from adding base to fresh urine to see if it will darken
Why does melanuria cause urine to blacken upon standing
Excess melanin from malignant melanoma
What does tumor secrete in melanuria
5,6 dihyroxyindole
Two major types of branched chain amino acid disorders
Maple syrup urine disease
organic acidemias
Burnt sugar odor
Maple syrup urine disease
Sweaty feet odor
Organic acidemias
What kind of amino acid issue is cystinuria
Renal aminoaciduria
What is the main issue in cystinuria
Cystine not reabsorbed by the kidney because of lack of enzyme
Diagnosis of cystinuria
Increased cystine, lysine, arginine, ornithine
Cystine crystals in urine
Cystinuria treatment
Keep urine at a n alkaline pH so crystals dont form
Cystinosis
Accumulation of cystine in the tissues
Two types of aminoacid urias
Overflow
Renal aminoaciduria
Two types of inborn errors of metabolism of amino acids
Aminoacidopathy
Organic acidemia
What is in excess in an aminoacidopathy?
Parent amino acid
What is in excess in an organic acidemia?
Metabolic products
Historic tests for IDing amino acid problems
Guthrie
Chemical tests
Urinalysis
Thin Layer Chromatography
Guthrie test
Agar, everything but amino acid of interest
Bacillus subtitles
If organism grows, that means there is high amounts of that amino acid present
Chemical testing
Color produced when reacts with ferric chloride
TLC
Specimen on medium
Medium in solvent
Amino acids move based on interaction with solvent
a.a. ID’d based on color and position
HPLC
As amino acids elute, they’re separated based on mass to charge ratio
When is newborn screening done?
When it can be caught in 24-48 hours
Can’t be tested based on clinical symptoms
There’s a test to identify it leading to treatment and intervention
Specimen requirements for newborn screening
Normal diet at least 24 hours prior
Fasting 6-8 hours
