Week 13 Flashcards
_______________ are an inactive form of enzymes also known as proenzymes and are how organisms protect themselves from their own digestive enzymes.
Zymogens
_____________ are proteases that cleave peptide (amide) linkages between amino acids.
Pancreatic enzymes.
________________ are enzymes that cleave peptides into smaller individual amino acids or small peptides (di- or tripeptides).
Peptidases
The enzyme pepsin is an ______________ protease.
Aspartyl.
The enzymes trypsin and chymotrypsin are _______________ proteases.
Serine.
Why would the active sites of trypsin and pepsin not function well in each other’s normal environment?
Trypsin is a serine protease- requires a neutral to basic environment to deprotonate serine.
Pepsin is an aspartyl protease- requires an acidic environment to readily protonate/deprotonate aspartate.
________________ is the process in which ammonia can be removed from an amino acid.
Transamination.
In transamination the _________________ is transferred to an α-keto acid (often pyruvate or α-ketoglutarate).
Amine.
__________________ is the enzyme that transaminates pyruvate to the amino acid alanine.
Alanine Transaminase
Alanine then travels from the muscle to the liver, where it can be transaminated to ________________ from __________________.
Glutamate, α-ketoglutarate.
__________________ is the process in which an amine is released as ammonia. Yields an α-keto acid and NADH/H+ is generated.
Oxidative Deamination
_________________ is commonly used and interconverted to α-ketoglutarate.
Glutamate
Free ______________ may be converted to waste products (in many organisms including mammals, urea).
Ammonia.
_________________ is the enzyme used to oxidatively deaminate glutamate and regenerate α-ketoglutarate.
Glutamate Dehydrogenase.
________________ is the metabolic process through which nitrogenous wastes generated in muscle are transferred to pyruvate, generating alanine; the alanine in turn is transported to the liver, where it is deaminated and the pyruvate presumably used in gluconeogenesis.
Glucose–Alanine Shuttle
________________ ATP-dependent enzyme responsible for the synthesis of glutamine from glutamate and ammonium ion in the liver.
Glutamine Synthetase
_________________ is the main enzyme that deaminates glutamine and yields glutamate and free ammonia.
Glutaminase
Amines are added to pyruvate in the ______ and removed from the resulting alanine in the ______.
A. liver; kidney
B. muscle; kidney
C. kidney; liver
D. muscle; liver
D. muscle; liver
In the urea cycle, Ornithine and Carbomyl phosphate undergo a condensation to give rise to _________________ and the enzyme responsible for this is _________________.
Citrulline. Ornthine transcarbamoylase.
In the urea cycle, cirtrulline is converted to ______________ by the enzyme _________________.
Argininosuccinate. Argininosuccinate synthase
In the urea cycle, _______________________is split off from argininosuccinate to yield _________________. The enzyme responsible for this step is __________________.
Fumarate, Arginine. Argininosuccinate lyase.
In the urea cycle, _______________ is cleaved off from arginine to generate _________________ by the enzyme________________.
Urea, Ornithine. Arginase.
The function of the urea cycle is to detoxify and dispose of _______________.
Ammonia.
________________ is the compound created from ammonia in order to reduce ammonia levels in the blood and lower the risk for toxicity.
Carbamoyl Phosphate
________________ is the enzyme involved in the production of carbamoyl phosphate for the urea cycle.
Carbamoyl phosphate synthetase I (CPS-1).
_______________ is the enzyme responsible for the production of building blocks for pyrimidine biosynthesis.
Carbamoyl phosphate synthetase II (CPS-2).
_________________ are organisms that typically eliminate wastes as ammonia secreted through the skin.
Ammonotelic
______________ are organisms that synthesize uric acid and eliminate it in their waste, which is technically not urine.
Uricotelic
Which amino acid is directly generated in the urea cycle?
Arginine
Amino acids can be broken down into two categories:
glucogenic and ketogenic.
_____________ are the amino acids that are broken down into products that undergo gluconeogenesis.
Glucogenic
______________ are the amino acids that metabolizes products into ketone bodies. Made from over abundance of Acetyl-CoA.
Ketogenic.
3 carbon skeleton amino acids are broken down into _______________.
Pyruvate.
Which amino acids are used in ketogenesis but not glucogenesis?
Leucine and lysine
________________ are molecules the body recognizes as foreign. Not molecules found in human metabolism and need to be eliminated. May be cleaved into smaller fragments.
Xenobiotics.
__________________ is the process by which the body detoxifies and eliminates foreign molecules.
Xenobiotic metabolism.
In _____________ of xenobiotic metabolism, Oxidation or cleavage occurs, xenobiotics become more hydrophilic and products are metabolically active.
Phase I
In _____________ of xenobiotic metabolism, conjugation to larger molecules such as glutathione or glucuronic acid.
Phase II
___________________ are
broad family of enzymes that employ NADPH and molecular oxygen (O2) to oxidatively modify substrate molecules. Membrane-associated enzymes commonly found in either the inner mitochondrial membrane or the endoplasmic reticulum.
Cytochrome P450
_______________ are enzymes that deactivate neurotransmitters. Covalently fix FAD+ to catalyze the conversion of a primary amine to an aldehyde.
Monoamine Oxidases.
_______________ oxidized form of glucose in which C-6 is oxidized to a carboxylic acid.
Glucuronic acid.
_________________ tripeptide of glycine, cysteine, and glutamate. Conjugated to xenobiotic via glutathione-S-transferase.
Glutathione (GSH).
___________________ is a network of highly porous capillaries that act as filters.
Large objects are retained in the capillaries, and small molecules are filtered out.
Glomerulus
_________________ is a peptide hormone that acts via a seven-transmembrane helix spanning receptor to elevate cytosolic levels of cAMP.
Antidiuretic Hormone.
Pyrimidine is synthesized from amino acids ______________ and ________________.
Glutamate and Aspartate.
Presence of carbamoyl phosphate synthetase in the mitochondria means we go through __________________ and presence in the cytoplasm means we go through ____________________.
Urea cycle. Pyrimidine bio-synthesis.
