Proteins Skildum Flashcards
Protein malnutrition is called?
Kwashiorkor
*Adequate calories but deficient specifically in protein
Pellega
Niacin def.
The protein whose loss causes cystic fibrosis normally functions as a…?
Chloride channel
The oxidized form of cysteine is called…?
Cystine
making a disulfide bond
The apoproteins ApoB100 and Apo B48 are encoded on the same gene. The different apoproteins are produced through…?
RNA editing
How does protein enter the blood?
As individual amino acids
What denatures proteins?
The low pH of the stomach
What cleaves a zymogen to activate it?
Peptidase
Why is secretion of proteases deficient in patients with CF?
Because of blockage of the pancreatic duct! This duct carries pancreatic enzymes into the lumen of the small intestine
*As a result they can be susceptible to protein malnutrition
How are amino acids transported across intestinal epithelial cells to the blood?
Secondary active transport using sodium
**Similar to SLGT in the kidney!
What transporter, when mutated, results in Hartnup Disease?
B0 (SLC6A9)
What is Hartnup Disease?
Tryptophan cannot be absorbed or reabsorbed by the sodium-dependent transporter so therefore cannot be used to synthesize niacin. This results in the sx of pellagra due to the niacin deficiency!
What is niacin used to make?
NADH and NADPH
What transporter, when mutated, causes cystinuria?
Why??
B0+ (SLC7A9)
This transporter brings in basic amino acids, without them…cystine congretates.
**Cystine congregates in proximal tubule causing kidney stone
Only enzyme that can break the bond between Glutamate and cysteine in glutathione?
Gamma-glutamyltranspeptidase
What is the outcome of gamma-glutamyltransptptidase?
Glutamate bonded to an amino acid along with a cysteinylglycine molecule!
*Transports an amino acid across cellular membranes but isn’t a major contributor to the transport of dietary amino acids but it IS important in glutathione synthesis.
What are the sources of the intracellular amino acid pool (3)?
Extracellular amino acids
Protein degradation
de novo synthesis from glycolysis or TCA cycle intermediates!
What type of hormone is insulin: catabolic or anabolic?
Anabolic
What complex activates protein synthesis and inhibits autophagy?
mTORC1
When activated, what inhibits protein synthesis and promotes autophagy?
AMPK
What is autophagy?
“self-eating”…The large scale version of turning proteins into amino acids
What is the key vitamin cofactor in protein metabolism?
What is it key for?
PLP-Pyridoxal phosphate
Transaminations, deaminations, carbon chain transfers
What is tetrahydrofolate (FH4) key for?
One carbon transfers
What is tetrahydrobiopterin (BH4) key for?
Ring hydroxylations
Ex. Phenylalanine –> Tyrosine requires this!
