inhibition

Examples of inhibition in the following topics:

• Control of Metabolism Through Enzyme Regulation

  • Sometimes it is necessary to inhibit an enzyme to reduce a reaction rate, and there is more than one way for this inhibition to occur.
  • Cells have evolved to use feedback inhibition to regulate enzyme activity in metabolism, by using the products of the enzymatic reactions to inhibit further enzyme activity.
  • For an example of feedback inhibition, consider ATP.
  • Competitive and noncompetitive inhibition affect the rate of reaction differently.
  • Feedback inhibition, where the end product of the pathway inhibits an earlier step, is an important regulatory mechanism in cells.

• Inhibiting Essential Metabolite Synthesis

  • An antimetabolite is a chemical that inhibits the use of a metabolite, a chemical that is part of normal metabolism.
  • An antimetabolite is a chemical that inhibits the use of a metabolite, a chemical that is part of normal metabolism.
  • For example, methotrexate is a folic acid analogue, and owing to structural similarity with folic acid, methotrexate binds and inhibits the enzyme dihydrofolate reductase, and thus prevents the formation of tetrahydrofolate.
  • Because tetrahydrofolate is essential for purine and pyrimidine synthesis, its deficiency can lead to inhibited production of DNA, RNA and proteins.
  • For example, azathioprine is the main immunosuppressive cytotoxic substance that is widely used in transplants to control rejection reactions by inhibiting DNA synthesis in lymphocytes.

• Antibiotic Classifications

  • Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics inhibit their growth or reproduction.
  • One way that bactericidal antibodies kill bacteria is by inhibiting cell wall synthesis.
  • Other ways that bactericidal antibiotics kill bacteria include inhibiting bacterial enzymes or protein translation.
  • The MIC (minimum inhibitory concentration) is the minimum concentration of drug which can inhibit the growth of the microorganism.
  • Tetracycline antibiotics are protein synthesis inhibitors, inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex.

• Inhibiting Cell Wall Synthesis

  • β-Lactam (beta-lactam) and glycopeptide antibiotics work by inhibiting or interfering with cell wall synthesis of the target bacteria.
  • Two types of antimicrobial drugs work by inhibiting or interfering with cell wall synthesis of the target bacteria.
  • This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. β-Lactam antibiotics are bacteriocidal and act by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls .
  • This class of drugs inhibit the synthesis of cell walls in susceptible microbes by inhibiting peptidoglycan synthesis.
  • Describe the two types of antimicrobial drugs that inhibit cell wall synthesis: beta-lactam and glycopeptide antibiotics

• Inhibiting Nucleic Acid Synthesis

  • Antimicrobial drugs inhibit nucleic acid synthesis through differences in prokaryotic and eukaryotic enzymes.
  • For example, the antimicrobial rifampin binds to DNA-dependent RNA polymerase, thereby inhibiting the initiation of RNA transcription.
  • For instance, quinolones inhibit DNA synthesis by interfering with the coiling of DNA strands.

• Kirby-Bauer Disk Susceptibility Test

  • A larger zone of inhibition around an antibiotic-containing disk indicates that the bacteria are more sensitive to the antibiotic in the disk.
  • KB tests are performed under standardized conditions and standard-sized zones of inhibition have been established for each antibiotic.
  • KB test results are usually reported as sensitive, intermediate, or resistant, based on the size of the zone of inhibition.
  • If the observed zone of inhibition is greater than or equal to the size of the standard zone, the microorganism is considered to be sensitive to the antibiotic.
  • Conversely, if the observed zone of inhibition is smaller than the standard size, the microorganism is considered to be resistant.

• Low Temperatures

  • Low temperatures usually inhibit or stop microbial growth and proliferation but often do not kill bacteria.
  • Low temperatures usually inhibit or stop microbial growth and proliferation but often do not kill bacteria.
  • Fridge temperatures inhibit the proliferation of bacteria better than molds and fungi.
  • Freezing food slows down decomposition by turning residual moisture into ice, inhibiting the growth of most bacterial species.

• Regulation of the Cell Cycle by External Events

  • External factors can influence the cell cycle by inhibiting or initiating cell division.
  • Both the initiation and inhibition of cell division are triggered by events external to the cell when it is about to begin the replication process.
  • A lack of HGH can inhibit cell division, resulting in dwarfism, whereas too much HGH can result in gigantism .
  • Crowding of cells can also inhibit cell division.

• Antiviral DNA Synthesis Inhibitors

  • Inhibiting DNA synthesis during viral replication is another key approach in battling viral infections.
  • Inhibiting DNA synthesis during viral replication is another approach to battle viral infections.
  • This inhibitor is active against the viral DNA polymerases at doses much lower than the ones needed to inhibit the human polymerases.
  • Hydroxycarbamide is thought to inhibit the enzyme ribonucleotide reductase.
  • The guanosine depicted in this specific image is used for RNA synthesis but acyclovir inhibits the synthesis of DNA synthesis.

• Naturally Occurring Antimicrobial Drugs: Antibiotics

  • An antimicrobial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans.
  • An antimicrobial is a substance that kills or inhibits the growth of microorganisms bacteria, fungi, or protozoans.
  • Toxins such as ricin also function via protein synthesis inhibition.
  • Rifamycin inhibits prokaryotic DNA transcription into mRNA by inhibiting DNA-dependent RNA polymerase by binding its beta-subunit.
  • Macrolides (as well as inhibiting ribosomal translocation and other potential mechanisms) bind to the 50s ribosomal subunits, inhibiting peptidyl transfer.