Enzyme Nomenclature and Classification

Sulfa drugs inhibit bacterial growth by competitively inhibiting the enzymes that normally react with PABA, preventing the synthesis of folic acid.

The main structural difference is that bacteria possess a cell wall, while human cells do not.

Transpeptidase cleaves terminal d-alanine and facilitates the cross-linking of peptidoglycan layers in the bacterial cell wall.

<p>Penicillins act as inhibitory substrates for transpeptidase due to their structural similarity to d-alanyl-d-alanine, allowing them to bind to the enzyme.</p> Signup and view all the answers

<p>Sulfa drugs are ineffective in humans because humans obtain folic acid preformed from dietary sources and do not synthesize it.</p> Signup and view all the answers

<p>Km represents the substrate concentration at which the reaction velocity, υ, equals half of the maximum velocity, vmax.</p> Signup and view all the answers

<p>Km is inversely related to the binding affinity; a greater Km means lower affinity.</p> Signup and view all the answers

<p>The Lineweaver-Burke plot transforms the Michaelis-Menten equation into a linear form, making it easier to estimate Km and vmax.</p> Signup and view all the answers

<p>When substrate concentration, S, is very low, Km becomes equal to S when the reaction velocity, υ, is half of vmax.</p> Signup and view all the answers

<p>Vmax is equivalent to the turnover number, denoting the maximum rate at which an enzyme converts substrate into product.</p> Signup and view all the answers

<p>An oxidase catalyzes oxidation reactions.</p> Signup and view all the answers

<p>One substrate is protein, and its corresponding enzyme is protease.</p> Signup and view all the answers

<p>Transferases catalyze the transfer of functional groups between two substrates.</p> Signup and view all the answers

<p>Lyases catalyze the addition or removal of groups to create or eliminate double bonds without hydrolysis. An example is a dehydratase, which removes water from a substrate.</p> Signup and view all the answers

<p>Racemases are enzymes that convert D isomers to L isomers or vice versa.</p> Signup and view all the answers

<p>Hydrolases catalyze the addition of a water molecule to break chemical bonds.</p> Signup and view all the answers

<p>Dehydrogenases introduce a double bond by removing hydrogen (H2) from a substrate.</p> Signup and view all the answers

<p>Enzyme names often include a prefix indicating the type of reaction followed by the substrate, such as 'glucose oxidase.'</p> Signup and view all the answers

<p>Protein modification can activate or inactivate an enzyme through the addition or removal of phosphate groups.</p> Signup and view all the answers

<p>Irreversible inhibitors bind tightly to enzymes and prevent the formation of the enzyme-substrate complex.</p> Signup and view all the answers

<p>Competitive inhibition occurs when an inhibitor with a similar structure competes with the substrate for the active site on the enzyme.</p> Signup and view all the answers

<p>Noncompetitive inhibition involves inhibitors that bind to sites other than the enzyme's active site, affecting the reaction without blocking substrate binding.</p> Signup and view all the answers

<p>Kinases are enzymes that add phosphate groups to proteins, while phosphatases are enzymes that remove them.</p> Signup and view all the answers

<p>A structural analog is a compound that closely resembles a substrate and competes for the active site on an enzyme, acting as a competitive inhibitor.</p> Signup and view all the answers

<p>Chemotherapy uses chemicals to selectively destroy infectious microorganisms without harming the host's cells, often impacting enzyme activities critical for microbial survival.</p> Signup and view all the answers

<p>Diisopropylphosphofluoridate (DIPF) is an example; it binds covalently to enzymes, leading to permanent inhibition.</p> Signup and view all the answers

<p>The slope represents Km/vmax, while the intercept on the ordinate is 1/vmax, allowing for the calculation of Km.</p> Signup and view all the answers

<p>Thiamine (B1); deficiency symptoms include fatigue, anorexia, nerve degeneration, paralysis, and heart failure.</p> Signup and view all the answers

<p>Riboflavin is associated with flavin mononucleotide and flavin adenine dinucleotide; deficiency symptoms include dermatitis, glossitis, and cataracts.</p> Signup and view all the answers

<p>Niacin (B3); its deficiency causes pellagra, characterized by scaly skin, muscle fatigue, diarrhea, and mental disorders.</p> Signup and view all the answers

<p>Coenzyme A is involved in many reactions of fatty acids, and notably, there is no known deficiency syndrome, although it may cause fatigue.</p> Signup and view all the answers

<p>Pyridoxine (B6) is linked to these reactions, with deficiency symptoms including dermatitis, fatigue, and anemia.</p> Signup and view all the answers

<p>Biotin is the coenzyme for CO2 fixation; its deficiency can lead to dermatitis, fatigue, anemia, nausea, and mental depression.</p> Signup and view all the answers

<p>Tetrahydrofolic acid is involved in various reactions with single carbon compounds; its deficiency can lead to abnormal red and white blood cells and gastrointestinal disturbances.</p> Signup and view all the answers

<p>Cyanocobalamine is involved in carbon chain isomerization and methyl group transfers; its deficiency can cause pernicious anemia and neurological disorders.</p> Signup and view all the answers

<p>Ascorbic acid is essential for collagen formation, protein metabolism, and iron absorption; deficiency symptoms include bleeding gums, slow healing wounds, and muscle pain.</p> Signup and view all the answers