Cyclo(Pro-Val) is a diketopiperazine (DKP) found widespread in marine microbes and resulting food products. With new bioactivities of cyclo(Pro-Val) being continually discovered, its potential applications in agriculture and food are becoming more evident, highlighting the need for efficient and practical methods to produce these compounds. However, the biosynthesis mechanisms of cyclo(Pro-Val), particularly in probiotics, remain unclear, and the functional identification of nonribosomal peptide synthases (NRPS) is still limited.
View Article and Find Full Text PDFGlypican-3 (GPC3) is a serological biomarker for the diagnosis of Hepatocellular carcinoma (HCC), but it is a challenging task to develop a bioassay for determination of the trace GPC3 in serum. In this study, Bioluminescense immunoassay based on bifunctional nanobody-nanoluciferase fusion was developed with the ultra-sensitive feature to achieve this goal. First, nanobodies special against GPC-3 binder as biological recognition element were generated by immunization and phage display technology.
View Article and Find Full Text PDFThe interaction between angiotensin I-converting enzyme (ACE) and the inhibitory peptide KNFL from Wakame was explored using isothermal titration calorimetry, multiple spectroscopic techniques and molecular dynamics simulations, and an inhibition model was established based on free energy binding theory. The experiments revealed that the binding of KNFL to ACE was a spontaneous exothermic process driven by enthalpy and entropy and occurred via multiple binding sites to form stable complexes. The complexes may be formed through multiple steps of inducing fit and conformational selection.
View Article and Find Full Text PDFPurification of peptides responsible for angiotensin I-converting enzyme (ACE) inhibitory activity from highly complex protein hydrolysates is difficult. Affinity chromatography is a powerful method for purification of peptides. In this study, a metal affinity-immobilized magnetic liposome (MA-IML) was prepared using lipid, N-hexadecyl iminodiacetic acid (HIDA) and magnetic nanoparticles made of FeCl·6HO and FeCl·4HO as main materials.
View Article and Find Full Text PDFAngiotensin-I-converting enzyme (ACE) inhibitory peptides derived from marine organism have shown a blood pressure lowering effect with no side effects. A new affinity medium of FeO@ZIF-90 immobilized ACE (FeO@ZIF-90-ACE) was prepared and used in the purification of ACE inhibitory peptides from Wakame () protein hydrolysate (<5 kDa). The FeO@ZIF-90 nanoparticles were prepared by a one-pot synthesis and crude ACE extract from pig lung was immobilized onto it, which exhibited excellent stability and reusability.
View Article and Find Full Text PDFAngiotensin-I-converting enzyme (ACE) inhibitory peptides derived from natural products have shown a blood pressure lowering effect with no side effects. In this study, two novel ACE inhibitory peptides (His-Leu-His-Thr, HLHT and Gly-Trp-Ala, GWA) were purified from pearl oyster () meat protein hydrolysate with alkaline protease by ultrafiltration, polyethylene glycol methyl ether modified immobilized metal ion affinity medium, and reverse-phase high performance liquid chromatography. Both peptides exhibited high ACE inhibitory activity with IC values of 458.
View Article and Find Full Text PDFCancer cells can develop in several ways to escape from death induced by chemotherapeutic agents, thereby weakening the anti-tumor efficacy of single-target chemotherapy. Therefore, the efficacy of conventional chemotherapy hits a single target in tumor cells subject to strict limits. In this article, an AS1411 aptamer-functionalized liposome is prepared, which can simultaneously deliver paclitaxel (PTX) and siRNA into MCF-7 cells and .
View Article and Find Full Text PDFCasein proteins were hydrolyzed by papain to identify inhibitory peptides of angiotensin I-converting enzyme (ACE). The hydrolysate was fractionized by immobilized metal affinity chromatography (IMAC-Ni). The fraction with high ACE inhibitory activity was enriched and further chromatographed on a reverse-phase column to yield four fractions.
View Article and Find Full Text PDFLizard fish protein hydrolysates (LFPH) were prepared from Lizard fish () proteins possessing powerful angiotensin I converting enzyme (ACE) inhibitory activity and the fraction (LFPH-I) with high ACE inhibitory activity was obtained through ultrafiltration. The active Fraction (F2) was isolated from LFPH-I using immobilized metal affinity chromatography (IMACNi). Analysis of amino acid levels revealed that F2 eluted from IMAC was enriched in Met, His, Tyr, Pro, Ile, and Leu compared to the crude peptide LFPH-I.
View Article and Find Full Text PDFIn this study, angiotensin converting enzyme (ACE) inhibitory peptides from lizard fish protein hydrolysate with neutral protease were purified through magnetic affinity separation. Magnetic agarose microsphere was prepared by reverse-phase microemulsion method, and its surface was modified with epoxy groups to immobilize ACE as a magnetic affinity medium (MAM-ACE) and then mixed with lizard fish ultrafiltration hydrolysate (<5 kDa). The MAM-ACE was recovered by a magnet.
View Article and Find Full Text PDFObjective: To study the chemical constituents of Bidens pilosa var. radiata.
Methods: The constituents were separated and purified with silica gel column, and identified by physicochemical properties and spectral methods.
Context: Angiotensin-converting enzyme (ACE) is one of the main regulators of blood pressure through its action on the renin-angiotensin system. ACE inhibitory peptides from natural materials inhibit ACE activity and have considerable importance as antihypertensive agents.
Objective: A new chromogenic reaction method for determining hippuric acid (HA) and angiotensin I-converting enzyme (ACE) inhibitor activity was developed.
Lizard fish (Saurida elongata) muscle protein was hydrolyzed using neutral protease to produce protein hydrolysate (LFPH), and the hydrolysis conditions were investigated using response-surface methodology. The optimum conditions for producing peptides with the highest angiotensin-I converting enzyme (ACE)-inhibitory activity were the following: enzyme-to-substrate ratio of 10,000 U/g, temperature of 48 °C, pH 7.0, and hydrolysis time of 2 h.
View Article and Find Full Text PDFDrug Dev Ind Pharm
June 2009
Background: If erythromycin is micronized into microspheres with suitable particle size, it can improve pulmonary drug concentration to maximize its effectiveness and minimize the adverse side effects.
Aim: In this study, erythromycin gelatin microspheres (EM-GMS) were prepared and some characteristics of EM-GMS were investigated. The drug-targeting index (DTI) of EM-GMS was evaluated to predict their potential as a targeted delivery system.