RESUMEN
In this study, the α-glucosidase (maltase-glucoamylase: MGAM) and α-amylase inhibitory properties elicited by xylooligosaccharides (XOSs) prepared from dulse xylan were analysed as a potential mechanism to control postprandial hyperglycaemia for type-2 diabetes prevention and treatment. Xylan was purified from red alga dulse powder and used for enzymatic hydrolysis using Sucrase X to produce XOSs. Fractionation of XOSs produced xylobiose (X2), ß-(1â3)-xylosyl xylobiose (DX3), xylotriose (X3), ß-(1â3)-xylosyl-xylotriose (DX4), and a dulse XOS mixture with n ≥ 4 xylose units (DXM). The different fractions exhibited moderate MGAM (IC50 = 11.41-23.44 mg/mL) and α-amylase (IC50 = 18.07-53.04 mg/mL) inhibitory activity, which was lower than that of acarbose. Kinetics studies revealed that XOSs bound to the active site of carbohydrate digestive enzymes, limiting access to the substrate by competitive inhibition. A molecular docking analysis of XOSs with MGAM and α-amylase clearly showed moderate strength of interactions, both hydrogen bonds and non-bonded contacts, at the active site of the enzymes. Overall, XOSs from dulse could prevent postprandial hyperglycaemia as functional food by a usual and continuous consumption.
Asunto(s)
Algas Comestibles , Glucuronatos , Hiperglucemia , Rhodophyta , alfa-Amilasas , Humanos , alfa-Glucosidasas , Hipoglucemiantes/farmacología , Xilanos/farmacología , Simulación del Acoplamiento Molecular , Oligosacáridos/farmacologíaRESUMEN
Mycosporine-like amino acids (MAAs) are the natural UV-absorbing compounds with antioxidant activity found in microalgae and macroalgae. We collected red algae Asparagopsis taxiformis, Meristotheca japonica, and Polysiphonia senticulosa from Nagasaki, where UV radiation is more intense than in Hokkaido, and investigated the effect of UV radiation on MAA content. It was suggested that A. taxiformis and M. japonica contained shinorine and palythine, while UV-absorbing compound in P. senticulosa could not be identified. The amounts of these MAAs were lower compared to those from Hokkaido. Despite an increase in UV radiation in both regions from February to April, MAA contents of red algae from Nagasaki slightly decreased while those from Hokkaido significantly decreased. This difference was suggested the amount of inorganic nitrogen in the ocean. Antioxidant activity of MAAs increased under alkaline conditions. The extract containing MAAs from P. senticulosa showed the highest antioxidant activity among 4 red algae.
Asunto(s)
Aminoácidos , Antioxidantes , Rhodophyta , Rhodophyta/química , Aminoácidos/análisis , Antioxidantes/química , Antioxidantes/farmacología , Japón , Rayos Ultravioleta , Compuestos de Bifenilo/antagonistas & inhibidores , Concentración de Iones de Hidrógeno , Ciclohexanoles , Ciclohexilaminas , Glicina/análogos & derivadosRESUMEN
In this study, we characterized the bioactive properties of three important brown seaweed species, Sargassum thunbergii, Undaria pinnatifida, and Saccharina japonica, by subcritical water extraction (SWE), as these species are well known for their beneficial health effects. Their physiochemical properties, including potential antioxidant, antihypertensive, and α-glucosidase inhibitory activity, and the antibacterial activity of the hydroysates were also analyzed. The highest total phlorotannin, total sugar content, and reducing sugar content in the S. thunbergii hydrolysates were 38.82 ± 0.17 mg PGE/g, 116.66 ± 0.19 mg glucose/g dry sample, and 53.27 ± 1.57 mg glucose/g dry sample, respectively. The highest ABTS+ and DPPH antioxidant activities were obtained in the S. japonica hydrolysates (124.77 ± 2.47 and 46.35 ± 0.01 mg Trolox equivalent/g, respectively) and the highest FRAP activity was obtained in the S. thunbergii hydrolysates (34.47 ± 0.49 mg Trolox equivalent/g seaweed). In addition, the seaweed extracts showed antihypertensive (≤59.77 ± 0.14%) and α-glucosidase inhibitory activity (≤68.05 ± 1.15%), as well as activity against foodborne pathogens. The present findings provide evidence of the biological activity of brown seaweed extracts for potential application in the food, pharmaceutical, and cosmetic sectors.
Asunto(s)
Algas Marinas , Agua , Agua/química , alfa-Glucosidasas , Antioxidantes/química , Antihipertensivos/análisis , Algas Marinas/química , Glucosa , Extractos Vegetales/farmacologíaRESUMEN
In this study, we studied the bioactive peptides produced by thermolysin hydrolysis of a water-soluble protein (WSP) from the red alga Gracilariopsis chorda, whose major components are phycobiliproteins and Ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCo). The results showed that WSP hydrolysate exhibited significantly higher ACE inhibitory activity (92% inhibition) compared to DPP-IV inhibitory activity and DPPH scavenging activity. The phycobiliproteins and RuBisCo of G. chorda contain a high proportion of hydrophobic (31.0-46.5%) and aromatic (5.1-46.5%) amino acid residues, which was considered suitable for the formation of peptides with strong ACE inhibitory activity. Therefore, we searched for peptides with strong ACE inhibitory activity and identified two novel peptides (IDHY and LVVER). Then, their interaction with human ACE was evaluated by molecular docking, and IDHY was found to be a promising inhibitor. In silico analysis was then performed on the structural factors affecting ACE inhibitory peptide release, using the predicted 3D structures of phycobiliproteins and RuBisCo. The results showed that most of the ACE inhibitory peptides are located in the highly solvent accessible α-helix. Therefore, it was suggested that G. chorda is a good source of bioactive peptides, especially ACE-inhibitory peptides.
Asunto(s)
Rhodophyta , Ribulosa-Bifosfato Carboxilasa , Humanos , Simulación del Acoplamiento Molecular , Péptidos/química , Rhodophyta/metabolismo , Ficobiliproteínas , Peptidil-Dipeptidasa A/químicaRESUMEN
The glycoside hydrolase family 17 ß-1,3-glucanase of Vibrio vulnificus (VvGH17) has two unknown regions in the N- and C-termini. Here, we characterized these domains by preparing mutant enzymes. VvGH17 demonstrated hydrolytic activity of ß-(1â3)-glucan, mainly producing laminaribiose, but not of ß-(1â3)/ß-(1â4)-glucan. The C-terminal-truncated mutants (ΔC466 and ΔC441) showed decreased activity, approximately one-third of that of the WT, and ΔC415 lost almost all activity. An analysis using affinity gel containing laminarin or barley ß-glucan revealed a shift in the mobility of the ΔC466, ΔC441, and ΔC415 mutants compared to the WT. Tryptophan residues showed a strong affinity for carbohydrates. Three of four point-mutations of the tryptophan in the C-terminus (W472A, W499A, and W542A) showed a reduction in binding ability to laminarin and barley ß-glucan. The C-terminus was predicted to have a ß-sandwich structure, and three tryptophan residues (Trp472, Trp499, and Trp542) constituted a putative substrate-binding cave. Linker and substrate-binding functions were assigned to the C-terminus. The N-terminal-truncated mutants also showed decreased activity. The WT formed a trimer, while the N-terminal truncations formed monomers, indicating that the N-terminus contributed to the multimeric form of VvGH17. The results of this study are useful for understanding the structure and the function of GH17 ß-1,3-glucanases.
Asunto(s)
Vibrio vulnificus , beta-Glucanos , Glucanos/química , Glicósido Hidrolasas/metabolismo , Especificidad por Sustrato , Triptófano , Vibrio vulnificus/genética , Vibrio vulnificus/metabolismo , beta-Glucanos/químicaRESUMEN
We recently demonstrated the monthly variation and antioxidant activity of mycosporine-like amino acids (MAAs) from red alga dulse in Japan. The antioxidant activity of MAAs in acidic conditions was low compared to that in neutral and alkali conditions, but we found strong antioxidant activity from the heated crude MAA fraction in acidic conditions. In this study, we identified and characterized the key compounds involved in the antioxidant activity of this fraction. We first isolated two MAAs, palythine, and porphyra-334, from the fraction and evaluated the activities of the two MAAs when heated. MAAs possess absorption maxima at around 330 nm, while the heated MAAs lost this absorption. The heated MAAs showed a high ABTS radical scavenging activity at pH 5.8-8.0. We then determined the structure of heated palythine via ESI-MS and NMR analyses and speculated about the putative antioxidant mechanism. Finally, a suitable production condition of the heated compounds was determined at 120 °C for 30 min at pH 8.0. We revealed compounds from red algae with antioxidant activities at a wide range of pH values, and this information will be useful for the functional processing of food.
Asunto(s)
Antioxidantes/química , Ciclohexanoles/química , Ciclohexanonas/química , Glicina/análogos & derivados , Rhodophyta/química , Benzotiazoles/química , Compuestos de Bifenilo/química , Glicina/química , Calor , Concentración de Iones de Hidrógeno , Japón , Espectroscopía de Resonancia Magnética , Estructura Molecular , Picratos/química , Espectrometría de Masa por Ionización de Electrospray , Ácidos Sulfónicos/químicaRESUMEN
One major pepsinogen, PG-I, and two minor pepsinogens, PG-II and PG-III were purified from lizardfish stomach by ammonium sulfate precipitation and two chromatographic columns. The three purified PGs migrated as single bands in native-PAGE gels with molecular weights (MW) ranging from 36 to 38 kDa. Each PG was converted to pepsin (P) at pH 2.0, and the MW were determined as 32 kDa (for P-I), 31 kDa (for P-II) and 30 kDa (for P-III). The optimum pH and temperature of pepsins were 2.0-3.5, and 40-50 °C. All 3 pepsins were strongly inhibited by pepstatin A. Divalent cations slightly stimulated the pepsin activities, but ATP had no effect on the pepsins. Purified pepsins were effective in the hydrolysis of various proteins. Km and kcat of the three pepsins for hemoglobin hydrolysis were 107.64-276.61 µM and 18.30-32.68 s-1, respectively. The new pepsins have potential for use in protein food procession and modification.
Asunto(s)
Pepsina A , Pepsinógenos , Secuencia de Aminoácidos , Animales , Peces/metabolismo , Pepsina A/metabolismo , Pepsinógenos/metabolismo , EstómagoRESUMEN
In a previous study, we found that the collagen peptides prepared from the by-products of Bester sturgeon had an inhibitory effect on elevated blood glucose levels in a glucose tolerance test with ICR mice. In the present study, we examine the mechanism of the effect of sturgeon collagen peptides (SCPs) in detail. When glucose was orally administered to mice along with the SCPs, it was found that the glucose remained in the stomach for a longer time. In the above tests, the amount of glucose excreted in the feces of mice also increased. On the contrary, it was revealed that the SCPs have a dipeptidyl-peptidase-IV (DPP-IV) inhibitory ability in an in vitro test. In subsequent oral and intravenous glucose administration tests, glucagon-like peptide-1 (GLP-1) and insulin levels in the blood of mice were maintained at high levels. These results suggested the following three mechanisms: SCPs slow the rate of transportation of glucose from the stomach into the small intestine, resulting in delayed glucose absorption; SCPs suppress the absorption of glucose in the small intestine and excrete it from the body; SCPs inhibit DPP-IV in the blood and maintain a high GLP-1 level in blood, which in turn stimulates insulin secretion.
Asunto(s)
Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Peces , Hipoglucemiantes/farmacología , Administración Oral , Animales , Organismos Acuáticos , Glucemia , Dipeptidil Peptidasa 4/efectos de los fármacos , Inhibidores de la Dipeptidil-Peptidasa IV/administración & dosificación , Inhibidores de la Dipeptidil-Peptidasa IV/química , Péptido 1 Similar al Glucagón/efectos de los fármacos , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/química , Infusiones Intravenosas , Ratones , Ratones Endogámicos ICRRESUMEN
More than 7000 red algae species have been classified. Although most of them are underused, they are a protein-rich marine resource. The hydrolysates of red algal proteins are good candidates for the inhibition of the angiotensin-I-converting enzyme (ACE). The ACE is one of the key factors for cardiovascular disease, and the inhibition of ACE activity is related to the prevention of high blood pressure. To better understand the relationship between the hydrolysates of red algal proteins and the inhibition of ACE activity, we attempted to identify novel ACE inhibitory peptides from Pyropia pseudolinearis. We prepared water soluble proteins (WSP) containing phycoerythrin, phycocyanin, allophycocyanin, and ribulose 1,5-bisphosphate carboxylase/oxygenase. In vitro analysis showed that the thermolysin hydrolysate of the WSP had high ACE inhibitory activity compared to that of WSP. We then identified 42 peptides in the hydrolysate by high-performance liquid chromatography and mass spectrometry. Among 42 peptides, 23 peptides were found in chloroplast proteins. We then synthesized the uncharacterized peptides ARY, YLR, and LRM and measured the ACE inhibitory activity. LRM showed a low IC50 value (0.15 µmol) compared to ARY and YLR (1.3 and 5.8 µmol). In silico analysis revealed that the LRM sequence was conserved in cpcA from Bangiales and Florideophyceae, indicating that the novel ACE inhibitory peptide LRM was highly conserved in red algae.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Fragmentos de Péptidos/farmacología , Peptidil-Dipeptidasa A/metabolismo , Proteínas de Plantas/farmacología , Rhodophyta/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/síntesis química , Inhibidores de la Enzima Convertidora de Angiotensina/aislamiento & purificación , Humanos , Hidrólisis , Simulación del Acoplamiento Molecular , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/aislamiento & purificación , Peptidil-Dipeptidasa A/química , Proteínas de Plantas/aislamiento & purificación , Unión Proteica , Conformación Proteica , Relación Estructura-ActividadRESUMEN
Red alga dulse contains xylan with ß(1â3)/ß(1â4) linkages. We previously prepared xylooligosaccharides (XOSs) from dulse xylan; however, the product contained many D-xylose residues and fewer XOSs with ß(1â3) linkages. To improve the efficiency of XOS production, we prepared two recombinant endoxylanases from Streptomyces thermogriseus (StXyl10 and StXyl11). Comparing the kcat/Km values for dulse xylan, this value from StXyl10 was approximately two times higher than that from StXyl11. We then determined the suitable conditions for XOS production. As a result, dulse XOS was prepared by the successive hydrolysis of 10 mg/mL dulse xylan by 0.5 µg/mL StXyl10 for 4 h at 50 °C and then 2.0 µg/mL StXyl11 for 36 h at 60 °C. Xylan was converted into 95.8% XOS, including 59.7% XOS with a ß(1â3) linkage and 0.97% D-xylose. Our study provides useful information for the production of XOSs with ß(1â3) linkages.
RESUMEN
Mycosporine-like amino acids (MAAs) are the ultraviolet (UV)-absorbable compounds, which are naturally produced by cyanobacteria and algae. Not only these algae but also marine organisms utilize MAAs to protect their DNA from UV-induced damage. On the other hand, the content of MAAs in algae was changed by the environmental condition and season. In addition to the UV-protected function, the antioxidant capacity of MAAs can apply to the cosmetic sunscreen materials and anti-cancer for human health. In this study, we developed the efficient extraction method of MAAs from red alga dulse in Usujiri (Hokkaido, Japan) and investigated the monthly variation. We also evaluated the antioxidant capacity. We employed the successive extraction method of water and then methanol extraction. Spectrophotometric and HPLC analyses revealed that the yield of MAAs by 6 h water extraction was the highest among the tested conditions, and the content of MAAs in the sample of February was the most (6.930 µmol g-1 dry weight) among the sample from January to May in 2019. Antioxidant capacity of MAAs such as crude MAAs, the purified palythine and porphyra-334 were determined by 2,2'-azinobis(3-ethylbenzothiazoline 6-sulfonic acid) (ABTS) radical scavenging and ferrous reducing power assays in various pH conditions, showing that the highest scavenging activity and reducing power were found at alkaline condition (pH 8.0).
Asunto(s)
Aminoácidos/química , Aminoácidos/farmacología , Antioxidantes/química , Fraccionamiento Químico/métodos , Rhodophyta/química , Benzotiazoles/química , Ciclohexanoles/química , Ciclohexanoles/farmacología , Concentración de Iones de Hidrógeno , Japón , Océano Pacífico , Ácidos Sulfónicos/químicaRESUMEN
Red alga dulse possesses a unique xylan, which is composed of a linear ß-(1â3)/ß-(1â4)-xylosyl linkage. We previously prepared characteristic xylooligosaccharide (DX3, (ß-(1â3)-xylosyl-xylobiose)) from dulse. In this study, we evaluated the prebiotic effect of DX3 on enteric bacterium. Although DX3 was utilized by Bacteroides sp. and Bifidobacterium adolescentis, Bacteroides Ksp. grew slowly as compared with ß-(1â4)-xylotriose (X3) but B. adolescentis grew similar to X3. Therefore, we aimed to find the key DX3 hydrolysis enzymes in B. adolescentis. From bioinformatics analysis, two enzymes from the glycoside hydrolase family 43 (BAD0423: subfamily 12 and BAD0428: subfamily 11) were selected and expressed in Escherichia coli. BAD0423 hydrolyzed ß-(1â3)-xylosyl linkage in DX3 with the specific activity of 2988 mU/mg producing xylose (X1) and xylobiose (X2), and showed low activity on X2 and X3. BAD0428 showed high activity on X2 and X3 producing X1, and the activity of BAD0428 on DX3 was 1298 mU/mg producing X1. Cooperative hydrolysis of DX3 was found in the combination of BAD0423 and BAD0428 producing X1 as the main product. From enzymatic character, hydrolysis of X3 was completed by one enzyme BAD0428, whereas hydrolysis of DX3 needed more than two enzymes.
Asunto(s)
Proteínas Bacterianas/metabolismo , Bifidobacterium adolescentis/enzimología , Glicósido Hidrolasas/metabolismo , Prebióticos , Rhodophyta/química , Xilanos/metabolismo , Proteínas Bacterianas/aislamiento & purificación , Biología Computacional , Disacáridos/metabolismo , Pruebas de Enzimas , Glicósido Hidrolasas/aislamiento & purificación , Hidrólisis , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Especificidad por Sustrato , Xilosa/metabolismoRESUMEN
Impacts of 2-butanol and ß-cyclodextrin (ß-CD) at various ratios and treatment times on bitterness, physicochemical and functional properties of Alcalase salmon frame protein hydrolysate (ASF) were investigated. ASF treated with 2-butanol at a ratio of 1:4 (w/v) for 20 min (ASFB) or with ß-CD at a ratio of 1:1 (w/w) for 30 min (ASF-C-1) had lower bitterness score than ASF (p < 0.05). Bitterness score of ASF (8.45) was reduced to the lowest score (1.32) when ASFB was subsequently treated with ß-CD at a 1:1 ratio (w/w) for 30 min (ASFB-C-1). Surface hydrophobicity of all debittered samples was lower than that of ASF sample (p < 0.05). The level of aromatic amino acids-containing peptides was reduced in ASFB-C-1 as shown by gel permeation chromatography. ASFB-C-1 sample had higher overall-likeness score but lower antioxidant properties than ASF (p < 0.05). The desired antioxidant activity could be achieved via increasing the amount of protein hydrolysate without imparting undesirable taste.
Asunto(s)
Antioxidantes/química , Proteínas de Peces en la Dieta/química , Salmo salar , Subtilisinas/química , beta-Ciclodextrinas/química , Animales , Butanoles/química , Proteínas de Peces en la Dieta/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Péptidos/química , Salmo salar/metabolismo , Alimentos Marinos , Subtilisinas/metabolismo , GustoRESUMEN
Inhibition of angiotensin I-converting enzyme (ACE) is one of the key factors to repress high blood pressure. Although many studies have been reported that seaweed protein hydrolysates showed the ACE inhibitory activity, the comprehensive understanding of the relationship was still unclear. In this study, we employed chloroplast genome for in silico analysis and compared it with in vitro experiments. We first extracted water-soluble proteins (WSP) from red alga Grateloupia asiatica, which contained mainly PE, PC, APC, and Rbc, and prepared WSP hydrolysate by thermolysin, resulting that the hydrolysate showed ACE inhibitory activity. Then, we determined the complete chloroplast genome of G. asiatica (187,518 bp: 206 protein-coding genes, 29 tRNA, and 3 rRNA) and clarified the amino acid sequences of main WSP, i.e., phycobiliproteins and Rubisco, to perform in silico analysis. Consequently, 190 potential ACE inhibitory peptides existed in the main WSP sequences, and 21 peptides were obtained by in silico thermolysin digestion. By comparing in vitro and in silico analyses, in vitro ACE inhibitory activity was correlated to the IC50 value from in silico digestion. Therefore, in silico approach provides insight into the comprehensive understanding of the potential bioactive peptides from seaweed proteins.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Proteínas de Cloroplastos/farmacología , Rhodophyta/química , Proteínas Algáceas/química , Proteínas Algáceas/aislamiento & purificación , Proteínas Algáceas/farmacología , Secuencia de Aminoácidos , Inhibidores de la Enzima Convertidora de Angiotensina/química , Inhibidores de la Enzima Convertidora de Angiotensina/aislamiento & purificación , Proteínas de Cloroplastos/química , Proteínas de Cloroplastos/aislamiento & purificación , Cloroplastos/genética , Simulación por Computador , Rhodophyta/genéticaRESUMEN
Protein hydrolysates were obtained from salmon frame using Alcalase or Flavourzyme at 3% (w/w protein) for 180 min. Protein hydrolysates prepared using Alcalase (HA) and Flavourzyme (HF) had DH and yield of 25.1-26.9% and 28.5-32.3 g/100 g sample, respectively. HF showed lower bitterness score (5.78) than that of HA (8.68) (P < 0.05). When HA and HF were further subjected to debittering with 2-butanol or isopropanol, the recovery of 77.88-81.60% was obtained (P < 0.05). HF and HA debittered with 2-butanol possessed less bitterness score, 3.60 and 3.77, respectively (P < 0.05). Surface hydrophobicity of 81.4 and 124.8 was attained when HF and HA were debittered with 2-butanol (P < 0.05). Selected debittered hydrolysates, produced using Flavourzyme, followed by fractionation using 2-butanol (HF-B) contained glutamic acid/glutamine (15.14 g/100 g), aspartic acid/asparagine (10.07 g/100 g) and glycine (9.30 g/100 g) as the predominant amino acids. HF-B had the decreased ABTS radical scavenging activity and metal chelating activity. A280 of peptides separated by gel filtration was lowered to some extent and coincided with the lower bitterness score and surface hydrophobicity. Thus, debittered protein hydrolysate from salmon frame could serve as a nutritive ingredient at high levels in health promoting foods.
RESUMEN
Protein hydrolysates from two forms of salmon frames named "chunk" and "mince" were produced and characterized. Both samples were subjected to hydrolysis using alcalase and papain at 1%-3% (w/w protein) for 0-240 min. Hydrolysate prepared with either protease at 3% for 180 min had the solid yield of 24.05%-26.39%. Hydrolysates contained 79.20%-82.01% proteins, 6.03%-6.34% fat, 9.81%-11.09% ash, and 4.02%-5.80% moisture. Amino acid profile showed that all hydrolysates had glutamic acid/glutamine (113.45-117.56 mg/g sample), glycine (77.86-86.18 mg/g sample), aspartic acid/asparagine (76.04-78.67 mg/g sample), lysine (61.97-65.99 mg/g sample), and leucine (54.30-57.31 mg/g sample) as the predominant amino acids. The size distributions determined by gel filtration chromatography varied, depending on proteases and the form of frame used for the hydrolysis. Different hydrolysates showed varying antioxidant capacities. Thus, protein hydrolysates from salmon frame could be used as a nutritive supplement in the protein deficient foods. PRACTICAL APPLICATIONS: Frames of salmon are by-products from salmon fish processing industries. The frames contained the remaining meat, hence they can be used for the preparation of protein hydrolysates. Generally, hydrolysates from fish by-products have been regarded as a promising food supplement, because they are rich in amino acids. Additionally, hydrolysates possess antioxidant activity, which is of health benefit. To produce the hydrolysate with less time consumption, the use of frame chunk instead of minced frame can be of better choice. Thus, frame of salmon, especially in chunk form, could be used as a raw material for production of protein hydrolysate using alcalase. The hydrolysate produced from salmon frame could serve as an alternative nutritive supplement to tackle the nutrition inadequacies in foods.
Asunto(s)
Antioxidantes/química , Proteínas de Peces/química , Hidrolisados de Proteína/química , Residuos/análisis , Animales , Biocatálisis , Manipulación de Alimentos , Hidrólisis , Papaína/química , Salmón , Subtilisinas/químicaRESUMEN
In this study, we investigated antioxidant activity of proteins from the red alga dulse (Palmaria sp.) harvested in Hokkaido, Japan. The dulse proteins that contain phycoerythrin (PE) as the main component showed a high radical scavenging activity. To clarify the key constituent of antioxidant activity in dulse proteins, we prepared recombinant dulse PE ß-subunit (rPEß) (apoprotein) and chromophores from the dulse proteins. As a result, the rPEß showed lower radical scavenging activity than that of dulse proteins. On the other hand, the dulse chromophores composed mainly of phycoerythrobilin (PEB) indicated extremely higher radical scavenging activity (90.4% ± 0.1%) than that of dulse proteins (17.9% ± 0.1%) on ABTS assay. In addition, on cell viability assay using human neuroblastoma SH-SY5Y cells, the dulse chromophores showed extracellular and intracellular cytoprotective effects against H2 O2 -induced cell damage. From these data, we concluded that the dulse proteins have antioxidant ability and the activity principally derives from the chromophores. PRACTICAL APPLICATION: Dulse is an abundant and underused resource, which contains a lot of proteins, especially phycoerythrin. We here demonstrated that the practically prepared dulse proteins possessed antioxidant activity and clarified that chromophores from the dulse proteins were the key components. Therefore, the dulse proteins have a potential for functional material.
Asunto(s)
Antioxidantes/química , Proteínas de Plantas/química , Rhodophyta/química , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Línea Celular , Humanos , Peróxido de Hidrógeno/toxicidad , Japón , Ficobilinas/química , Ficobilinas/aislamiento & purificación , Ficobilinas/farmacología , Ficoeritrina/química , Ficoeritrina/aislamiento & purificación , Ficoeritrina/farmacología , Proteínas de Plantas/aislamiento & purificación , Proteínas de Plantas/farmacologíaRESUMEN
Plastid proteins are one of the main components in red algae. In order to clarify the angiotensin I converting enzyme (ACE) inhibitory peptides from red alga Palmaria sp. (Japan), we determined the plastid genome sequence. The genome possesses 205 protein coding genes, which were classified as genetic systems, ribosomal proteins, photosystems, adenosine triphosphate (ATP) synthesis, metabolism, transport, or unknown. After comparing ACE inhibitory peptides between protein sequences and a database, photosystems (177 ACE inhibitory peptides) were found to be the major source of ACE inhibitory peptides (total of 751). Photosystems consist of phycobilisomes, photosystem I, photosystem II, cytochrome complex, and a redox system. Among them, photosystem I (53) and II (51) were the major source of ACE inhibitory peptides. We found that the amino acid sequence of apcE (14) in phycobilisomes, psaA (18) and psaB (13) in photosystem I, and psbB (11) and psbC (10) in photosystem II covered a majority of bioactive peptide sequences. These results are useful for evaluating the bioactive peptides from red algae.
Asunto(s)
Rhodophyta/genética , Secuencia de Aminoácidos , Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Simulación por Computador , Genoma de Plastidios , Sistemas de Lectura Abierta , Péptidos/metabolismo , Péptidos/farmacología , Rhodophyta/metabolismo , Secuenciación Completa del GenomaRESUMEN
Trypsin from Japanese dace (Tribolodon hakonensis) (JD-T) living in freshwater (2-18 °C) was purified. JD-T represented typical fish trypsin characteristics regarding the effects of protease inhibitor, calcium-ion, and pH. For the effect of temperature, JD-T quite resembled to the trypsins from tropical-zone marine fish and freshwater fish (the catfish cultured in Thailand), i.e., the optimum temperature was 60 °C, and it was stable below 60 °C at pH 8.0 for 15 min incubation. From the data, it seemed that the trypsin from freshwater fish is thermostable in spite of the fact that their habitat temperatures are low. So, we determined the primary structure of JD-T to discuss its thermostability-structure relationship. JD-T possessed basic structural features of fish trypsin such as the catalytic triad, the Asp189 residue for substrate specificity, 12 Cys residues forming six disulfide-bridges, and the calcium-ion-binding loop. On the other hand, the contents of charged amino acid residues in whole JD-T molecule (16.2%) and N-terminal region (13.8%) were similar to those of tropical-zone marine fish and other freshwater fish trypsins. Then, JD-T conserved the five amino acid residues (Glu70, Asn72, Val75, Glu77, and Glu80) coordinate with calcium-ion, and the proportion of negatively charged amino acids to charged amino acids in the calcium-ion-binding region of JD-T (75.0%) was equivalent to those of tropical-zone marine fish and freshwater fish trypsins. Therefore, it was suggested that the high thermostability of JD-T are stemmed from these structural specificities.