Protein digestion Flashcards
exam 4
source of nitrogen-containing substances in the body, including proteins, heme, nucleic acids
Amino acids
used for fuel or for making glucose
excess amino acids
aa pool of blood supplies aa’s to
tissues
where is pepsin found?
stomach
where is trypsin found?
small intestine
where is chymotrypsin found?
small intestine
where is elastase found?
small intestine
where is carboxypeptidase found?
small intestine
propetide of pepsin binds at
high pH
pepsin is active at
low pH
which organ secretes bicarbonate to neutralize stomach contents?
Pancreas
pancreas is stimulated by ____ to release bicarbonate
CCK
key enzyme to convert zymogens to active enzyme
trypsin
released from the cells lining the small intestine to initiate trypsinogen conversion to trypsin
enteropeptidase
biochemical basis of inherited forms of pancreatitis stems from
overactive trypsin
mutations in trypsin
reduce binding to its inhibitor
transported across membranes using transporters that are specific for groups of aa
amino acids
amino acids are brought into cells typically using a
sodium-linked transporter
disease that results from a
defective transport
defective transport in cystinuria also leads to
elevated lysine because it uses the same transporter
build up of cystein leads to
cystine-based deposits in the kidney
loss of tryptophan because of a defective transporter
Hartnup
hartnup leads to
tryptophan deficiency
made from tryptophan
Niacin
D3: dementia, diarrhea, dermatitis
deficiency in niacin- Pellagra
difference btween Pellagra and Hartnup?
high tryptophan in urine in Hartnup
intracellular proteins recognized by _____________ and are tagged by _____________ and degraded by the ________
intracellular proteins recognized by E3 ubiquitin-ligase and are tagged by polyubiquitin and degraded by the proteasome
An initiating ______ ligates uniquitin to an E3 bound substrate
E2
signals for protein to be tagged can be
within the amino acid sequences
example of a signal within aa
identity of the N-terminal aa
HPV E6 protein to recruit E6-AP, an E3 ubiquitin ligase
facilitator protein
recognizes and ubiquitinates p53
E6-AP
products of proteosome are
short peptides
the short peptides are degraded to aa by
cellular proteases
example of an E3-type ubiquitin ligase that is associated with Parkinson’s disease
Parkin