Protein Metabolism
Serotonin and melatonin are made from which amino acid?
tryptophan
What occurs in the stomach due to a low pH (<3)?
denaturing of proteins
What are the end products of protein digestion that can be absorbed?
free amino acids, and di and tri-peptides
Proteins can be classified as ___ and ___ based on which precursors they supply
glucogenic and ketogenic
What are the major fuel sources for muscle?
glucose and fatty acids
What is the result of deamination of a protein?
keto-acid and ammonia
which cells produce pepsinogen in the stomach?
chief cells
Peptide transport into the enterocyte occurs through which carrier protein?
PEPT 1
Which nitrogen containing compound functions as a buffer, an antioxidant, and lowers the calcium threshold for muscle contraction?
carnosine
How long does the fed state last after eating?
3 hours
Homocysteine can use which two pathways to be re-methylated into methionine?
the choline-dependent pathway, and the B12 and folate-dependent pathway
The pancreas produces which zymogens?
trypsinogen, chymotrypsinogen, procarboxypeptidases A + B, and proelastase
Carrier proteins of amino acids into the enterocyte often require which ion?
sodium
What does the alanine cycle bring to the liver?
Nitrogen
During the post-absorptive state, which hormone rises?
glucagon
norepinephrine is produced from which amino acid?
tyrosine
The enterocytes in the small intestine produce which enzymes?
aminopeptidases, dipeptidyl aminopeptidases, and tripeptidases
Carrier proteins are often specific to what?
Specific to the amino acid
Protein quality measured through PDCAAS measures which two things?
limiting AA, digestibility
Which major hormone is considered anabolic?
insulin
Which amino acid is converted to tyrosine? And what is the disease that results from a mutation of the enzyme that catalyzes this reaction?
phenylalanine, PKU
Which enzyme begins the process of activating pancreatic zymogens into enzymes?
enteropeptidase
What is the first stop for most amino acids/peptides after absorption?
the liver
There are 4 protein structures. Which protein structure describes just the amino acid sequence of the protein?
primary structure
Which energy system that supplies muscle with ATP is used during the first few seconds of high intensity exercise?
creatine system