The ACE inhibitors have sequences ranging 2–12 amino acids in length, with
Leu, Ile, Val, Lys, and Arg residues in the C-terminal region, and showed to be
responsible for the most significant inhibition [107]. Aromatic residues of amino
acid located in the C-terminal such as Trp, Tyr, Phe, and Pro, in any of the
three-terminal possible positions, also exhibited inhibitory effects of enzyme
activity through interaction with different subsites of the catalytic structure of the
ACE [108].
Daliri et al. [109] recently reviewed the antihypertensive properties of peptides
released from whey proteins.
5.4 Antimicrobial Peptides
Because of the emergence of new multidrug-resistant bacteria (MDR), there is a
need to find and develop new antimicrobial agents. Antimicrobial peptides (AMPs)
are a particular subset of peptides that play an important role in the defense
mechanisms of numerous organisms. Studies on the structure and sequence of
peptides with antimicrobial activity show that they are generally positively charged
(cationic), with a high proportion of hydrophobic residues. Antimicrobial peptide
sequences include 10–50 amino acids with hydrophobic residues and a cationic and
anionic charge (e.g., Lys, Arg, Ala, Leu, among others) in which the latter has a
substantial contribution to the amphipathic characteristics of these bioactive peptides [110].
These characteristics allow AMPs to selectively bind to the negatively charged
microbial membranes through electrostatic interactions, leading to disturbances in
the integrity of the bacterial cytoplasmic membrane. The resulting interaction leads
to cytoplasm loss by leakage of cell content by different suggested mechanisms.
The damage to the integrity of the lipid bilayer is conceivable to interfere or leading
directly or indirectly to cell death [111].
The inhibition of biopolymer synthesis can also result in cell death. For example,
peptidoglycan biosynthesis is essential to maintain cell integrity and function. Thus,
any disturbance in its synthesis may culminate in the death of the microbial cell that
may occur due to the contribution of multiple independent or cooperative mechanisms. Even when acting on the same microbial species, different mechanisms can
prevail, depending on environmental factors, the phase of growth, and the presence
of immunological responses [112].
The antimicrobial action of AMPs is broad spectrum because they act on bacterial membranes and other more generic intracellular targets such as DNA, unlike
most antibiotics that generally are active against specific targets such as proteins.
Such characteristic mechanisms of action allow AMPs to avoid the most common
resistance mechanism observed for traditional antibiotics and, therefore, the
development of resistance is more unlikely [113].
In recent decades, the impact of AMPs released from dairy proteins on human
health and the production of new functional food ingredients were subject to
intensive research. Bovine or human lactoferrin exhibits antimicrobial activity
Enzymatic Production of Bioactive Peptides from Whey Proteins …
495
Leu, Ile, Val, Lys, and Arg residues in the C-terminal region, and showed to be
responsible for the most significant inhibition [107]. Aromatic residues of amino
acid located in the C-terminal such as Trp, Tyr, Phe, and Pro, in any of the
three-terminal possible positions, also exhibited inhibitory effects of enzyme
activity through interaction with different subsites of the catalytic structure of the
ACE [108].
Daliri et al. [109] recently reviewed the antihypertensive properties of peptides
released from whey proteins.
5.4 Antimicrobial Peptides
Because of the emergence of new multidrug-resistant bacteria (MDR), there is a
need to find and develop new antimicrobial agents. Antimicrobial peptides (AMPs)
are a particular subset of peptides that play an important role in the defense
mechanisms of numerous organisms. Studies on the structure and sequence of
peptides with antimicrobial activity show that they are generally positively charged
(cationic), with a high proportion of hydrophobic residues. Antimicrobial peptide
sequences include 10–50 amino acids with hydrophobic residues and a cationic and
anionic charge (e.g., Lys, Arg, Ala, Leu, among others) in which the latter has a
substantial contribution to the amphipathic characteristics of these bioactive peptides [110].
These characteristics allow AMPs to selectively bind to the negatively charged
microbial membranes through electrostatic interactions, leading to disturbances in
the integrity of the bacterial cytoplasmic membrane. The resulting interaction leads
to cytoplasm loss by leakage of cell content by different suggested mechanisms.
The damage to the integrity of the lipid bilayer is conceivable to interfere or leading
directly or indirectly to cell death [111].
The inhibition of biopolymer synthesis can also result in cell death. For example,
peptidoglycan biosynthesis is essential to maintain cell integrity and function. Thus,
any disturbance in its synthesis may culminate in the death of the microbial cell that
may occur due to the contribution of multiple independent or cooperative mechanisms. Even when acting on the same microbial species, different mechanisms can
prevail, depending on environmental factors, the phase of growth, and the presence
of immunological responses [112].
The antimicrobial action of AMPs is broad spectrum because they act on bacterial membranes and other more generic intracellular targets such as DNA, unlike
most antibiotics that generally are active against specific targets such as proteins.
Such characteristic mechanisms of action allow AMPs to avoid the most common
resistance mechanism observed for traditional antibiotics and, therefore, the
development of resistance is more unlikely [113].
In recent decades, the impact of AMPs released from dairy proteins on human
health and the production of new functional food ingredients were subject to
intensive research. Bovine or human lactoferrin exhibits antimicrobial activity
Enzymatic Production of Bioactive Peptides from Whey Proteins …
495