Enzymes — Flashcards

Flashcard 1: Sigmoid-shaped graph which is a property of _____ enzymes

Answer: multimeric

Flashcard 2: lead inhibits _____ and _____ enzymes

Answer: ALA dehydratase

Extra: 

Flashcard 3: Ethanol may be converted to _____ via the enzyme alcohol dehydrogenase

Answer: acetaldehyde

Flashcard 4: When using an irreversible competitive inhibitor, the _____ changes, while the Km remains the same

Answer: Vmax

Flashcard 5: When using a _____ inhibitor, the Vmax changes, while the Km remains the same

Answer: noncompetitive

Flashcard 6: When using a _____ inhibitor, the Km changes, while the Vmax remains the same

Answer: reversible competitive

Flashcard 7: Dihydrofolate may be converted to _____ via the enzyme dihydrofolate reductase

Answer: tetrahydrofolate

Flashcard 8: Propionyl-CoA carboxylase requires _____, biotin, and CO2

Answer: ATP

Flashcard 9: Many _____ (ethnicity) are deficient of the ethanol metabolism enzyme acetaldehyde dehydrogenase

Answer: Asians

Flashcard 10: Elastin is broken down by the enzyme _____, which is normally inhibited by 1-antitrypsin

Answer: elastase

Flashcard 11: _____ is a serine protease cleaves at the carboxy-terminal of bulky hydrophobic amino acids like tryptophan, phenylalanine, and tyrosine.

Answer: Chymotrypsin

Flashcard 12: If the amount of enzymes doubles, the Vmax _____, while Km remains constant

Answer: doubles

Flashcard 13: What enzymes (2) reduce hydrogen peroxide (H2O2) to O2 and H2O? _____ and glutathione peroxidase

Answer: Catalase

Flashcard 14: The three enzyme components of Pyruvate dehydrogenase complex are: Pyruvate dehydrogenase, Dihydrolipoyl _____ and Dihydrolipoyl dehydrogenase

Answer: transacetylase

Flashcard 15: _____ catalyze the conversion of cyclic endoperoxides i.e.,PGG2 and PGH2 into PGI2

Answer: Synthase

Flashcard 16: Once I- has been pumped into the cell for thyroid hormone synthesis, it is _____ to I2 by the enzyme thyroid peroxidase in the follicular cell membrane

Answer: oxidized

Flashcard 17: _____ is converted into fructose and glucose by the enzyme sucrase

Answer: Sucrose

Flashcard 18: _____ is a serine protease cleaves at the carboxy-terminal of basic amino acids like arginine and lysine

Answer: Trypsin

Flashcard 19: _____ catalyze the conversion of cyclic endoperoxides i.e., PGG2 and PGH2 into PGE2 and PGD2

Answer: Isomerases

Flashcard 20: _____ is an enzyme that catalyzes the conversion of angiotensinogen to angiotensin I in the plasma

Answer: Renin

Flashcard 21: Pancreatic and salivary _____ hydrolyze 1,4-glycosidic bonds in starch

Answer: -amylases

Flashcard 22: H2CO3 is converted into _____ and CO2 by carbonic anhydrase

Answer: H2O

Flashcard 23: Once in the CNS, L-DOPA may be converted to _____ via the enzyme DOPA decarboxylase

Answer: dopamine

Flashcard 24: _____ catalyze the conversion of PGE2 into PGF2a

Answer: Reductase

Flashcard 25: _____ serves as the allosteric activator of muscle glycogen phosphorylase.

Answer: 5'AMP

Flashcard 26: In a _____-order reaction, rate is proportional to the square of the concentration of one reactant.

Answer: second

Flashcard 27: The diagnosis of G6PD deficiency is confirmed via _____ studies, which are performed weeks after a hemolytic episode resolves

Answer: enzyme

Flashcard 28: In the first step of fibrinolysis, _____ is converted to plasmin via tissue plasminogen activator (tPA)

Answer: plasminogen

Flashcard 29: _____ cleaves high-molecular-weight kininogen (HMWK) to bradykinin

Answer: Kallikrein

Flashcard 30: _____ may be converted to H2O via the enzyme glutathione peroxidase

Answer: H2O2

Flashcard 31: Protein C and S normally _____ factors Va and VIIIa

Answer: inactivate

Flashcard 32: Enzymes that use metal-ion as a _____ are termed as metalloenzymes

Answer: prosthetic group

Flashcard 33: _____ glutathione may be converted to oxidized glutathione via the enzyme glutathione peroxidase

Answer: Reduced

Flashcard 34: _____ glutathione may be converted to reduced glutathione via the enzyme glutathione reductase

Answer: Oxidized

Flashcard 35: Enzymes that use metal-ion as a _____ are termed as metal-activated enzymes.

Answer: cofactor

Flashcard 36: H2O2 is converted to _____ by the enzyme myeloperoxidase (oxidative burst)

Answer: HClO- (hypochlorite)

Flashcard 37: _____ is a serine protease that cleaves at the carboxy-terminal of neutral amino acids like alanine and glycine.

Answer: Elastase

Flashcard 38: In red blood cells (in plasma), _____ is combined with H2O via the enzyme carbonic anhydrase, forming H2CO3

Answer: CO2

Flashcard 39: The enzyme glutathione _____ requires a molecule of NADPH, which is provided by the activity of the enzyme G6PD

Answer: reductase

Flashcard 40: Isocitrate dehydrogenase is regulated via negative feedback by _____ and NADH

Answer: ATP

Flashcard 41: Factor X of the coagulation cascade may be activated by factor _____ with factor VIII as a cofactor (intrinsic pathway)

Answer: IX

Flashcard 42: The Michaelis-Mentin constant, Km is defined as the _____ concentration at which rate is equal to Vmax/2

Answer: substrate

Flashcard 43: While most enzymatic reactions follow a hyperbolic curve (Michaelis-Menten kinetics), _____ kinetics follow a sigmoidal curve

Answer: allosteric

Flashcard 44: The _____ of I2 into thyroglobulin is mediated by the enzyme thyroid peroxidase

Answer: organification

Flashcard 45: Phosphofructokinase-1 is regulated via negative feedback by _____ and citrate

Answer: ATP

Flashcard 46: _____ may be converted to norepinephrine via the enzyme dopamine -hydroxylase (with vitamin C as a cofactor)

Answer: Dopamine

Flashcard 47: _____ and Catalase are two enzymes contained in aerobic organisms

Answer: Superoxide dismutase

Flashcard 48: Dopamine in the CNS may be degraded to _____ via the enzyme catechol-O-methyltransferase (COMT)

Answer: 3-methoxytyramine (3-MT)

Flashcard 49: Chymotrypsinogen is a _____ whereas its active form Chymotrypsin is a serine protease.

Answer: zymogen

Flashcard 50: All members of the tribe _____ have the enzyme phenylalanine deaminase which converts phenylalanine to phenyl pyruvic acid called the PPA reaction.

Answer: Protea

Flashcard 51: The first step in intestinal protein digestion involves activation of _____ (inactive) to trypsin (active)

Answer: trypsinogen

Flashcard 52: _____ activates factor XII, which initiates the intrinsic pathway of the coagulation cascade

Answer: Subendothelial collagen

Flashcard 53: In the _____ cells of the ovary, testosterone is converted to 17-estradiol via the enzyme aromatase

Answer: granulosa

Flashcard 54: Pepsinogen (inactive) is converted into _____ (active) in the presence of H+

Answer: pepsin

Flashcard 55: Activation energy of an enzyme is free energy difference between the _____ & transition State.

Answer: Substrate

Flashcard 56: Leydig cells do not contain the steroid hormone enzymes _____ or 11-hydroxylase and, therefore, cannot synthesize glucocorticoids or mineralocorticoids

Answer: 21-hydroxylase

Flashcard 57: Acetaldehyde may be converted to _____ via the enzyme acetaldehyde dehydrogenase

Answer: acetate

Flashcard 58: In cells containing mineralocorticoid receptors, _____ may be converted to cortisone by the enzyme 11-hydroxysteroid dehydrogenase

Answer: cortisol

Flashcard 59: The rate of a reaction depends on the concentration of both the _____ and the substrate

Answer: enzyme

Flashcard 60: Dopamine in the CNS may be degraded to _____ via the enzyme MAO-B

Answer: DOPAC

Flashcard 61: _____ is an obligate activator of pyruvate carboxylase

Answer: Acetyl-CoA

Flashcard 62: Catalase and GSH belong to the category of _____ antioxidants

Answer: preventive

Flashcard 63: _____ is present at higher levels in men than in women for alcohol metabolism

Answer: Gastric alcohol dehydrogenase (Enzyme)

Flashcard 64: _____ converts active cortisol to inactive cortisone.

Answer: 11-beta-HSD2 (11-beta-hydroxysteroid dehydrogenase2)

Flashcard 65: Which compound inhibits enolase enzyme in the glycolysis pathway?_____

Answer: Fluoride

Flashcard 66: Which element is a part of enzymes ferroxidase and ferroportin?_____

Answer: Copper

Flashcard 67: Lathyrus odoratus/ Sweet pea causes lathyrism by inhibiting _____

Answer: Lysyl oxidase

Flashcard 68: Aromatase (CYP_____) converts testosterone to estradiol.

Answer: 19

Flashcard 69: Galactosyl transferase is a marker for _____

Answer: golgi apparatus (cell organelle)

Flashcard 70: Aconitase is an _____ containing enzyme.

Answer: iron (mineral)

Flashcard 71: Which ion is a part of enzyme dopamine hydroxylase?_____

Answer: Copper

Flashcard 72: Enzyme increases the rate of reaction by reducing the _____

Answer: activation energy.

Flashcard 73: Which metal is a co-factor for superoxide dismutase?_____

Answer: Zinc

Flashcard 74: Which element is a part of enzyme Glutathione peroxidase?_____

Answer: Selenium

Flashcard 75: Which LDH isozyme is found in the Brain, Kidney, Lungs, Spleen, pancreas?_____

Answer: LDH-3

Flashcard 76: Which substance is an inhibitor of alpha-ketoglutarate dehydrogenase?_____

Answer: Arsenite (element)

Flashcard 77: Which metal is a co-factor for alcohol and lactate dehydrogenase?_____

Answer: Zinc

Flashcard 78: Which ion is a part of enzyme amine oxidase?_____

Answer: Copper

Flashcard 79: _____ are enzymes that catalyze the same reaction, but differ in AA sequence, Subunit composition, Electrophoretic mobility, Tissue localization and Substrate affinity

Answer: Isoenzymes

Flashcard 80: The prosthetic group present in dinitrogenase is _____.

Answer: Molybdenum

Flashcard 81: The plot of initial reaction velocity against substrate concentration is _____.

Answer: hyperbolic

Flashcard 82: Alanine on pyruvate kinase is an example of _____competitive inhibition

Answer: non-

Flashcard 83: Which LDH isozyme is found in the Heart?_____

Answer: LDH-1

Flashcard 84: Which element is a part of enzyme tyrosinase?_____

Answer: Copper

Flashcard 85: The catalytic efficiency of an enzyme is expressed as the ratio of _____

Answer: Kcat/Km.

Flashcard 86: Serine proteases, aminotransferases and pyruvate carboxylase are examples of _____ reactions

Answer: Ping-pong

Flashcard 87: The Michaelis-Menten equation illustrates mathematically the relationship between Vi and [S] i.e, _____

Answer: Vi = Vmax [S]/Km+[S]

Flashcard 88: Lithium heparin when used for anticoagulation, may cause inhibition of _____ activity

Answer: acid phosphatase (enzyme)

Flashcard 89: Which enzymes catalyze the cleavage of C-C, C-O, C-N, and other covalent bonds by atom elimination, thereby generating double bonds?_____

Answer: Lyases

Flashcard 90: Caspases are cysteine proteases that cleave proteins at the _____ residue

Answer: aspartic acid

Flashcard 91: Enzymes which incorporate two atoms of oxygen into a substrate are known as _____

Answer: Di-oxygenases

Flashcard 92: Elevated _____ is the most common abnormal liver function test (LFT) in pyogenic liver abscess.

Answer: serum alkaline phosphatase (ALP) level (enzyme)

Flashcard 93: Carbonic Anhydrase _____ is present on the inside of the PCT tubular cell

Answer: II

Flashcard 94: Which element is a part of enzyme Superoxide dismutase?_____

Answer: Copper

Flashcard 95: Which metal is a co-factor for carbonic anhydrase?_____

Answer: Zinc

Flashcard 96: When the substrate concentration is much greater than the Km value, the reaction follows _____-order kinetics.

Answer: zero

Flashcard 97: The _____ is the factor by which the rate of a biologic process increases for a 10C increase in temperature.

Answer: temperature coefficient (Q10)

Flashcard 98: Thio_____ is a succinyl CoA- acetoacetyl CoA transferase

Answer: phorase

Flashcard 99: A _____ enzyme is one which undergoes self-destruction in order to terminate its own activity

Answer: suicidal

Flashcard 100: The clotting pathway is kicked off in the body by _____.

Answer: tissue factor

Flashcard 101: The activation of Lysyl hydroxylases _____ healing.

Answer: promotes (delays/promotes)

Flashcard 102: Which compound is an inhibitor of cis-aconitate?_____

Answer: Fluoroacetate

Flashcard 103: The DICER belongs to which class of enzyme?_____

Answer: Endonucleases

Flashcard 104: Factor _____ is also known as clot-stabilizing factor that converts unstable fibrin clot into a stable clot.

Answer: XIII

Flashcard 105: Which LDH isozyme is found in the Liver and skeletal muscle?_____

Answer: LDH-4 and LDH-5

Flashcard 106: Which LDH isozyme is found in the Blood?_____

Answer: LDH-2

Flashcard 107: Which element inhibits the enzyme phosphoglycerate kinase of glycolysis?_____

Answer: Arsenate

Flashcard 108: Acid phosphatase and cathepsin are markers for _____

Answer: lysosome (cell organelle)

Flashcard 109: Which compound is an inhibitor of succinate dehydrogenase?_____

Answer: Malonate

Flashcard 110: Glucose-6-phosphate on hexokinase is an example of _____competitive inhibition

Answer: non-

Flashcard 111: _____ are a family of NAD-dependent protein deacetylases.

Answer: Sirtuins (Protein class)

Flashcard 112: What is the rate limiting enzyme in catecholamine synthesis?_____

Answer: Tyrosine hydroxylase

Flashcard 113: Glycogen synthase belongs to the _____ group of enzymes.

Answer: transferase

Flashcard 114: Glutamine synthetase is classified as a _____

Answer: ligase::Enzyme class

Flashcard 115: Chymotrypsinogen is a _____.

Answer: zymogen

Flashcard 116: _____ is required for the conversion of dihydrobiopterin to tetrahydrobiopterin (BH4).

Answer: Dihydropteridine reductase

Flashcard 117: Sigmoid-shaped graph which is a property of _____ enzymes

Answer: multimeric