4. Role of Amino Acids, Peptides, Proteins for Anti-hypertension Flashcards
(21 cards)
Overview of proteins and bioactive peptides
- proteins are a source of bioactive peptides that are NOT active
- Release and activation can be done by enzymatic work in vitro/in digestive system
- After being absorbed in ACTIVE form, can perform various biological and biochem function (improve metabolism and health)
Concept of biological function of food proteins now
Food proteins and fragments of derivative peptides can participate in general metabolism more interactively – through bioactivity in addition to function of nutrients
Bioactivity of proteins
- Certain proteins are naturally bioactive and can be absorbed by intestines whole/slightly modified form
- Proteins can run specific bioactivity in systemic metabolism in GI, or be resistant to digestive enzymes and exhibit different bioactivity
- Food proteins contain specific amino acids sequences in polypeptide chain–when cut to peptides can run a variety of bioactivity such as that of the original protein
Bioactive peptides
short-chain protein molecules (<20 amino acid residues) that have physiological benefits when ingested in the body → reduce the risk of cardiovascular disease, tumor cell growth, and blood sugar levels
Mr of peptides and subsequent effects
- low (< 10kDa)
- More resistant to (less easily degraded) enzymatic hydrolysis as it passes GI tract
- Structural degradation may cause peptides less or inactive; but in some cases can make it more active or easily absorbed
- More easily absorbed by blood, easily transported throughout body
Benefits of bioactive peptides
- positive influence on cardiovascular, digestive, endocrine, immune, and nervous systems
- Potential as antihypertensive, antioxidant, opioid antagonist, antibacterial, antithrombotic, and immunomodulatory compound
- Some peptides exhibit multifunctional properties
- Activity determined by composition and sequencing of amino acid
Production of bioactive peptides
- found naturally
- result of protein cutting (non natural)
Processes:
- enzymatic hydrolysis during digestion
- fermentation
- maturation in food processing
- proteolysis w proteolytic enzymes
Biological activity of protein/peptide of milk
- carrier of mineral
- body protection
– lectoferin and pathogen defense - immunoglobin
- alpha-lactalbumin (source of tryptophan)
- bifidogenic activity
- other components in milk
milk peptide as carrier of minerals
- casein contains Ca and P
- (biologically) protects mammary glands against calcification/precipitation control of calcium phosphate
- specific fragments in beta/kappa-casein as carriers of those minerals
milk peptides for body protection
- protection against cancer
- tumor index increase in animals given dimethylhydrazine (carcinogen), decrease in rats given casein/whey protein/meat diet/soy flour
- whey protein most effective
- suspected FA and bile involved in hyperproliferation of intestinal epithelial cells (higher fat > more carcinogens)
- high amt of sulfur AA (met, cys), limiting amino acid in glutation biosynthesis
milk peptides for lactoferin and pathogen defence
Lactoferin: Fe binding glycoprotein (transferin grp) in breast milk, mammalian milk
- non specific defense against pathogens
- activity against microbes: gram +/-, yeast, fungi
- antiviral activity: cytomegalovirus, influenza, hepatitis (inhibition of absorption process of viral particles through binding to both host cells and viral particles)
- protection of WBC oxidation by Fe
- control of immune response during inflammation
Mechanism of lactoferin
- Affinity for Fe is high, bacterial cells lack Fe, bacteria stops growing
- Bacterial cell membranes disruptedm loses integrity of phagocytosis
- Stimulation by macrophage and monocytes
Milk protein as immunoglobulin
- high content in colostrum
- concentration decreases in normal lactation period
- effective in preventing and fighting bacteria
Milk protein as alpha lactalbumin
- biological role in human milk is interaction with galactotransferase
- transfers galactose from UDP-galactose to glucose to form lactose
- rich in AA cys and try
- try and metabolites are important for nerve cells
Milk peptides for bifidogenic activity
- stimulation of bifidobacterium
- ALA and lactoferin spurs growth of bifidobacterium sp
Other factors in milk
- minor bioactive components: hormones and growth factor
- extract growth factor from cheese whey, reduce damage in rats treated with methotrexate
- growth factors improve intestines after radiation or chemo
- also contains protein binding vit b12, folate, riboflavin
- milk fat globule on membrane contains glycoprotein (butyrofilin) which is an immune component
Biological activity of peptide
- Casein phosphopeptide (CPP)
- Glycomacropeptide (GMP)
- Angiotensin-1 Converting Enzyme Inhibitor (ACEI)
- Other bioactive peptides
Casein phosphopeptide (CPP)
- Phosphosrine rich AA sequencing in alpha/beta-casein prevents calcification by regulating calcium phosphate deposition
- CPP increases bioavailability of Fe, Ca and Zn
Glycomacropeptide (GMP)
- C-terminal side 64 amino acid residue of kappa-casein, set free by rennet in cheese making
- Easily formed during digestion, allowing extretion of gastric fluid and regulation of digestion
- Milk clotting paralle to blodd clotting; GMP derived peptides can be developed as active peptides in the formation of platelets
- GMP containing oligosaccharides, stimulates growth of bifidobacteria
Angiotensin-1 Converting Enzyme Inhibitor (ACEI)
- [ACE] Enzyme for BP regulation
- Removes 2 AA from angiotensin I > angiotensin II octapeptide: potential clogged vessels
- [ACEI] prevent synthesis of angiotensin II, BP decrease
Other bioactive peptides
- Casamorphins: small peptide derivatives of beta casein > increases intestinal transit type > increases electrolyte absorption
