• Journal of Microbiology and Biotechnology
• /
• v.7 no.1
• /
• pp.49-51
• /
• 1997

In order to obtain a hybrid synthetic peptide with a more potent antifungal activity than magainin-2 but without hemolytic activity, four hybrid peptides were designed from the sequences of magainin 2 and cecropin A and their antifungal activities against Trichosporon beigelii were investigated. The result showed that analogue 2 and 4 exhibited better antifungal activity against T. beigelii than magainin-2 but no hemolytic activities. The peptides, therefore, could be used as models for the development of potent antifungal peptides.

• Mass Spectrometry Letters
• /
• v.1 no.1
• /
• pp.5-8
• /
• 2010

In the present study, collisionally-activated dissociation (CAD) experiments were performed under low energy collision conditions in six peptides containing a disulfide bond. Fragments produced as a result of the cleavage of a disulfide bond were obtained after CAD in four peptides (bactenecin, TGF-$\alpha$, cortistantin, and linearly linked peptide, Scheme 1) with basic amino acid residues. In contrast, the CAD analysis of two peptides with no basic residue (oxytocin and tocinoic acid) rarely produced fragments indicative of cleavage of a disulfide bond. These results are consistent with the mobile proton model suggested by the McLuckey and O'air groups (ref. 22 and 23); nonmobile protons sequestered at basic amino acid residues appear to promote the cleavage of disulfide bonds.

• Mass Spectrometry Letters
• /
• v.6 no.3
• /
• pp.80-84
• /
• 2015

Here, we demonstrate the use of MALDI-TOF as a fast and simple analytical approach to evaluate the DNA-binding capability of various peptides. Specifically, by varying the amino acid sequence of the peptides consisting of lysine (K) and tryptophan (W), we identified peptides with strong DNA-binding capabilities using MALDI-TOF. Mass spectrometric analysis reveals an interesting novel finding that lysine residues show sequence selective preference, which used to be considered as mediator of electrostatic interactions with DNA phosphate backbones. Moreover, tryptophan residues show higher affinity to DNA than lysine residues. Since there are numerous possible combinations to make peptide oligomers, it is valuable to introduce a simple and reliable analytical approach in order to quickly identify DNA-binding peptides.

• Journal of Pharmaceutical Investigation
• /
• v.30 no.2
• /
• pp.73-83
• /
• 2000

Polyethylene glycol (PEG) is a water soluble, biocompatible, non-toxic polymer and PEGylation is a well established technique for the modification of therapeutic proteins and peptides. PEG-protein drugs have been extensively studies in relation to therapies for various diseases: cancer, inflammation and others. The covalent attachment of PEG to proteins and peptides prolonged plasma half-life, reduced antigenicity and immunogenicity, increased thermal and mechanical stability, and prevented degradation by enzymes. Several chemical groups for general and site specific conjugation have been exploited to activate PEG for amino group, carboxyl group, and cysteine groups. PEGylation of many proteins and peptides have been studied to enhance their properties for the potential uses. Also, the different positional isomers in several PEG-proteins have shown the difference in vivo stability and biological indicating that the site of PEG molecule attachment is one of the important factor to develop PEG-proteins as potential therapeutic agents.

• Journal of Nutrition and Health
• /
• v.26 no.5
• /
• pp.585-592
• /
• 1993

In order to investigate the hypocholesteremic effect of soybean perptides, soybean protein(ISP), casein(CNP), their peptic hydrolyzates fractionated by acid precipitation at different pH's(SHT, SH8, SH6, SH4, CHT, CH5, CH4) and amino acid mixtures of the same composition as the proteins(SAA, CAA) were fed to rats and the concentration of serum cholesterol was measured. Then in vitro digestibility and molecular weight distribution of the peptides by pepticpancreatic hydrolysis was measured by FPLC. The lower the in vitro digestibility of peptides is, the lower the concentration of serum cholesterol becomes(r=0.986) and the higher the ratio of macropeptides is, the lower the concentration of serum cholesterol becomes(r=-0.932) in rats. These results suggest that the in vitro digestibility of peptides has close relationship to the concentration of serum cholesterol in rats and non-digestible meacropeptides or polypeptides especially more than 1 kDa, formed through digestion in gut, may lower the serum cholesterol in rats.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.7
• /
• pp.591-594
• /
• 1995

The influence of protecting groups on the β-sheet-structure-stability of protected peptides was studied in organic solvents. α-amino groups, carboxyl groups and side chain functional groups of model peptides were protected by suitable groups commonly used in peptide synthesis. The difference of the solubilities of model peptides was investigated by the solvent-titration method by using IR absorption spectra. The β-sheet structure of model peptide in CH2Cl2 was easily disrupted by increasing the amounts of DMSO. The β-sheet-structure-stabilizing potentials of each protecting group showed similar behaviors except Npys, Mts and Z2. The result exhibits that the < SPβ > values of protected peptides are almost independent of the kinds of their protecting groups.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.3
• /
• pp.288-298
• /
• 2023

Host defense peptides are expressed in various immune cells, including phagocytic cells and epithelial cells. These peptides selectively alter innate immune pathways in response to infections by pathogens, such as bacteria, fungi, and viruses, and modify the subsequent adaptive immune environment. Consequently, they play a wide range of roles in both innate and adaptive immune responses. These peptides are of increasing importance due to their broad-spectrum antimicrobial activity and their functions as mediators linking innate and adaptive immune responses. This review focuses on the pleiotropic biological functions and related mechanisms of action of human host defense peptides and discusses their potential clinical applications.

• KSBB Journal
• /
• v.17 no.3
• /
• pp.261-265
• /
• 2002

The biologically active peptides in human blood can adjust the functions of many physiological systems. The peptides in human blood were separated on the five steps of linear gradient-elution mode by RP-HPLC with UV detection. The size of commercially available $C_{18}$ chromatographic column was 4.60$\times$150 mm with particle size of 5 $\mu\textrm{m}$ and pore size of 100 $\AA$. The mobile phases used were water in 0.75% trifluoroacetic acids (TFA) and organic modifier of acetonitrile. The isolation methods suggested in this work for peptides from the blood were composed of the formation of immiscible liquid layers and precipitation by centrifuge and chemicals of sodium citrate and trichloroacetic acid (TCA). The some peptides were identified based on the retention times previously constructed database.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.3
• /
• pp.381-390
• /
• 2018

We have previously derived a novel antimicrobial peptide, LPcin-YK3(YK3), based on lactophoricin and have successfully studied and reported on the relationship between its structure and function. In this study, antimicrobial peptides with improved antimicrobial activity, less cytotoxicity, and shorter length were devised and characterized on the basis of YK3, and named YK5, YK8, and YK11. The peptide design was based on a variety of knowledge, and a total of nine analog peptides consisted of one to three amino acid substitutions and C-terminal deletions. In detail, tryptophan substitution improved the membrane perturbation, lysine substitution increased the net charge, and excessive amphipathicity decreased. The analog peptides were examined for structural characteristics through spectroscopic analytical techniques, and antimicrobial susceptibility tests were used to confirm their activity and safety. We expect that these studies will provide a platform for systematic engineering of new antibiotic peptides and generate libraries of various antibiotic peptides.

• Biomolecules & Therapeutics
• /
• v.9 no.3
• /
• pp.218-223
• /
• 2001

In the present study, we intended to investigate whether polycationic peptides including poly-L-lysine (PLL) and poly-L-arginine (PLA) specifically inhibit the mucin release and do not affect significantly the release of the other releasable glycoproteins with less molecular weight than mucin's from cultured airway goblet cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 hr and chased for 30 min in the presence of varying concentrations of either poly-L-arginine (PLA) or poly-L-lysine (PLL) to assess the effects on 3H-mucin release and on the total elution profile of the treated culture medium. The results were as follows : (1) PLL 78,000, PLL 9,600 and PLA 8,900 inhibited mucin release in a dose-dependent manner; (2) These polycationic peptides did not inhibit the release of the other releasable glycoproteins with less molecular weights than mucin's. We conclude that these polycationic peptides 'specifically'inhibit mucin release from airway goblet cells. This finding suggests that these polycationic peptides might be used as a specific airway mucin-regulating agent.