ABSTRACT
Mulberry seed oil (MSO) is a kind of potential health-care lipids. This study, we investigated unsaturated fatty acids profiles of freshly squeezed MSO by GC-MS and modulated an oil-in-water emulsion system stabilized by acid hydrolyzed egg albumin (AHEA) to protect MSO from oxidation. The results showed that the content of total unsaturated fatty acids in MSO was almost 80%, of which 9, 12- and 10, 13-linoleic acid was over 60% and 10% respectively. In the case of the MSO-in-AHEA emulsions, it was observed that acid hydrolysis improved emulsifying effect, emulsifying stability and antioxidant activity of egg albumin (EA). The hydrolysates of EA (1%, w/w) acid hydrolyzed for 4â¯h at 85⯰C had the best DPPH radical scavenging efficiency. It was suitable for EA to hydrolyze for 4 to 12â¯h at pHâ¯2.5 and 85⯰C because of their better emulsification and oxidation stability than the others. The results about AHEA could be valuable for designing delivery and protect systems for MSO or other bioactive component to avoid their oxidative damage or control their release.
Subject(s)
Albumins/chemistry , Antioxidants/chemistry , Egg Proteins/chemistry , Emulsifying Agents/chemistry , Fatty Acids, Unsaturated/analysis , Food Handling/methods , Morus/chemistry , Plant Oils/chemistry , Seeds/chemistry , Biphenyl Compounds/chemistry , Emulsions , Gas Chromatography-Mass Spectrometry , Hydrogen-Ion Concentration , Hydrolysis , Oxidation-Reduction , Particle Size , Picrates/chemistry , Plant Oils/isolation & purification , Rheology , Temperature , Time FactorsABSTRACT
A novel serine protease with fibrinolytic activity named CSP was purified from the culture supernatant of the fungus Cordyceps sinensis, a kind of Chinese herbal medicine. Analysis of the purified enzyme by SDS-PAGE indicated that CSP was a single polypeptide chain with an apparent molecular weight of 31 kDa, and N-terminal sequencing revealed that the first ten amino acid residues of the enzyme were Ala-Leu-Ala-Thr-Gln-His-Gly-Ala-Pro-Trp-. When casein was used as a substrate, the proteolytic activity of CSP reached its maximum at pH 7.0 and 40 degrees C. The effect of chemical agents on the enzyme activity indicated that CSP is a serine protease with a free cysteine residue near the active site. It hydrolysed fibrinogen, fibrin and casein with a high efficiency, while hydrolysing bovine serum albumin (BSA) and human serum albumin (HSA) to a lesser extent. CSP was found to be a plasmin-like protease, but not a plasminogen activator, and it preferentially cleaved the A alpha chain of fibrinogen and the alpha-chain of fibrin. Therefore, the extracellular protein CSP may represent a potential new therapeutic agent for the treatment of thrombosis.
Subject(s)
Cordyceps/enzymology , Fibrinolysis/physiology , Serine Endopeptidases/isolation & purification , Amino Acid Sequence , Fibrin/metabolism , Fibrinogen/metabolism , Hydrogen-Ion Concentration , Serine Endopeptidases/chemistry , Substrate Specificity , TemperatureABSTRACT
A novel method for the determination of peroxynitrite using folic acid as a fluorescent probe is described. The method is based on the oxidation of the reduced, low-fluorescent folic acid by peroxynitrite to produce a high-fluorescent emission product. The fluorescence increase is linearly related to the concentration of peroxynitrite in the range of 3x10(-8) to 5.0x10(-6)molL(-1) with a correlation coefficient of 0.998, and the detection limit is 1x10(-8)molL(-1). Interferences from some metal ions normally seen in biological samples, and also some anions structurally similar to peroxynitrite were studied. The optimal conditions for the detection of peroxynitrite were evaluated.
