16 Questions
Explain the difference between peptides and proteins based on their molecular mass.
Peptides have a molecular mass of less than 10,000 Da, while proteins have a molecular mass of 10,000 Da or more.
What are the components of a peptide chain and how are they linked together?
Peptide chains are composed of amino acids linked together by peptide bonds, with an N-terminal (amine group) and C-terminal (carboxyl group) residue at the ends.
What are oligopeptides and provide examples of oligopeptides?
Oligopeptides are chains of fewer than twenty amino acids. Examples include dipeptides, tripeptides, and tetrapeptides.
How are peptides classified and what are they often bound to in a biologically functional way?
Peptides are classified based on their sources and functions. They are often bound to ligands such as coenzymes and cofactors, to other proteins or macromolecules, or to complex macromolecular assemblies.
What are nonribosomal peptides assembled by and where are they common?
Nonribosomal peptides are assembled by enzymes and are common in unicellular organisms, plants, and fungi.
What are peptones derived from and what are they used for?
Peptones are derived from animal milk or meat digested by proteolysis and are used in nutrient media for growing bacteria and fungi.
What percentage of protein-protein interactions in human cells are mediated by peptides?
Approximately 15-40% of protein-protein interactions in human cells are mediated by peptides.
What do peptide fragments help identify or quantify, and what are they products of?
Peptide fragments are used to identify or quantify the source protein and can be products of enzymatic degradation or natural degradation.
What are the categories of peptide families mentioned in the text?
The peptide families include ribosomal peptides, antimicrobial peptides, tachykinin peptides, vasoactive intestinal peptides, pancreatic polypeptide-related peptides, opioid peptides, calcitonin peptides, self-assembling peptides, and other peptides.
What does the terminology related to peptides include?
The terminology related to peptides includes polypeptide, protein, oligopeptide, and naming of peptides based on the number of amino acids in their chain.
What do nonribosomal peptides often contain and what indicates their synthesis?
Nonribosomal peptides are often cyclic and can have highly complex cyclic structures, while the presence of oxazoles or thiazoles often indicates their synthesis.
What percentage of the pharmaceutical market is estimated to be based on peptide products?
Peptides have significant pharmaceutical applications, with an estimated 10% of the pharmaceutical market being based on peptide products.
What do peptones contain and why are they valuable in nutrient media?
Peptones contain small peptides, fats, metals, salts, vitamins, and other biological compounds, making them valuable in nutrient media for bacterial and fungal growth.
What are some examples of post-translational modifications of peptides mentioned in the text?
Post-translational modifications of peptides include phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation, and disulfide formation.
What is the estimated percentage of protein-protein interactions in human cells mediated by peptides?
Approximately 15-40% of protein-protein interactions in human cells are mediated by peptides.
What are nonribosomal peptides synthesized by and what are they common in?
Nonribosomal peptides are synthesized by modular enzyme complexes called nonribosomal peptide synthetases and are common in unicellular organisms, plants, and fungi.
Study Notes
Handbook of Biologically Active Peptides Overview
- Peptides are categorized into various groups including plant, bacterial, fungal, invertebrate, amphibian, venom, cancer, vaccine, immune, brain, endocrine, gastrointestinal, cardiovascular, and respiratory peptides.
- Post-translational modifications of peptides include phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation, and disulfide formation.
- Nonribosomal peptides are assembled by enzymes and are common in unicellular organisms, plants, and fungi. They are synthesized by modular enzyme complexes called nonribosomal peptide synthetases.
- Peptones are derived from animal milk or meat digested by proteolysis and are used in nutrient media for growing bacteria and fungi.
- Peptide fragments are used to identify or quantify the source protein and can be products of enzymatic degradation or natural degradation.
- Peptides can interact with proteins and other macromolecules, playing important roles in cell signaling and immune modulation. Approximately 15-40% of protein-protein interactions in human cells are mediated by peptides.
- The peptide families include ribosomal peptides, antimicrobial peptides, tachykinin peptides, vasoactive intestinal peptides, pancreatic polypeptide-related peptides, opioid peptides, calcitonin peptides, self-assembling peptides, and other peptides.
- The terminology related to peptides includes polypeptide, protein, oligopeptide, and naming of peptides based on the number of amino acids in their chain.
- A monopeptide has one amino acid, a dipeptide has two amino acids, a tripeptide has three amino acids, and so on, with specific examples given for each.
- Nonribosomal peptides are often cyclic and can have highly complex cyclic structures, while the presence of oxazoles or thiazoles often indicates their synthesis.
- Peptides have significant pharmaceutical applications, with an estimated 10% of the pharmaceutical market being based on peptide products.
- Peptones contain small peptides, fats, metals, salts, vitamins, and other biological compounds, making them valuable in nutrient media for bacterial and fungal growth.
Test your knowledge of biologically active peptides with this quiz. Explore the diverse categories, post-translational modifications, synthesis pathways, and pharmaceutical applications of peptides. Learn about peptide families, terminology, and their role in cell signaling and immune modulation.
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