α-amylase is an endonucleoside hydrolase that hydrolyzes the α-1, 4-glycosidic bonds inside polysaccharides, such as starch, to generate oligosaccharides, dextrins, maltotriose, maltose and a small amount of glucose. Due to the importance of α-amylase in food industry, human health monitoring and pharmaceuticals, detection of its activity is widely required in the breeding of α-amylase producing strains, in vitro diagnosis, development of diabetes drugs, and the control of food quality. In recent years, many new α-amylase detection methods have been developed with improved speed and sensitivity. This review summarized recent processes in the development and applications of new α-amylase detection methods. The major principle of these detection methods were introduced, and their advantages and disadvantages were compared to facilitate future development and applications of α-amylase detection methods.
Humans ; alpha-Amylases/chemistry* ; Polysaccharides ; Oligosaccharides ; Starch ; Maltose

OBJECTIVETo extract polysaccharides from Dioscorea opposita by alpha-amylase and ultrasound.

METHODThe optimum condition of enzyme-assisted extraction has been obtained through orthogonal test according to the yield of polysaccharides.

RESULTA higher yield of polysaccharides was achieved at 55 degrees C, pH 5.5 , with a load of alpha-amylase 10 mg for 1.0 hour, the extraction rate was increased by in compare of sonolysis treatment alone.

CONCLUSIONTo carry out an enzyme treatment before ultrasound--assisted extraction elevated the yield of polysaccharides.

Dioscorea ; chemistry ; Hydrogen-Ion Concentration ; Polysaccharides ; chemistry ; isolation & purification ; metabolism ; alpha-Amylases ; metabolism

Glucocorticoids/urine* ; Humans ; Hydrocortisone ; Marathon Running ; Saliva/chemistry* ; alpha-Amylases/analysis*

The inclusion complex of isotretinoin was prepared by sealed-control temperature method and amylose was used as carrier. The formation of inclusion complex was confirmed by powder X-ray diffraction and DSC. The equation of enzymatically-controlled drug release was established by kinetic theory, and the release characteristic of drug was confirmed by using the kinetic equation. The results show that the drug release was attributed to first order reaction without alpha-amylase. However, with alpha-amylase, the drug release was an acceleration process by the effect of both dissociation and enzymatic hydrolysis simultaneously. The research indicates that drug release from the inclusion complex was modulated by the addition of alpha-amylase.
Amylose ; chemistry ; Calorimetry, Differential Scanning ; Dermatologic Agents ; chemistry ; Drug Carriers ; chemistry ; Hydrolysis ; Isotretinoin ; chemistry ; Kinetics ; Temperature ; X-Ray Diffraction ; alpha-Amylases ; chemistry

Supplement effects of ions, sugars, and amino acids on the thermostability of liquefying type alpha-amylase from Bacillus subtilis were examined. The addition of 1 mmol/L Ca2+ or about 50 mmol/L Na+ remarkably stimulated the thermostability of this enzyme among ions examined. The thermostability of the enzyme was enhanced and reduced by the extrinsic addition of 50 mmol/L acidic amino acid such as glutamic acid and alkaline amino acid of the concentrations of sugars from 0 to 1000 mmol/L the thermostability of alpha-amylase increased almost such as arginine, respectively. With the increases linearly. By the co-existence of Na+ or K+ with some amino acids or sugars the thermostability of this enzyme was fairly increased. The changes in the fluorescence intensity of alpha-amylase were examined as a function of the incubation temperature on the enzyme, which showed a good agreement with those of residual activities.
Amino Acids ; pharmacology ; Calcium ; pharmacology ; Carbohydrates ; pharmacology ; Enzyme Stability ; Protein Conformation ; Sodium ; pharmacology ; Temperature ; alpha-Amylases ; chemistry ; metabolism

Thermostable alpha-amylase from Pyrococcus furious is an important industrial enzyme in brewing and alcohol production. Eexpression of the thermostable a-amylase in plants can reduce greatly costs in the production of alcohol using crop plants. A chloroplast expression vector, p64A, containing the thermostable alpha-amylase gene from Pyrococcus furious, was constructed with clpP-trnL-petB-chlL-rp123-rpl2 as Chlamydomonas reinhardtii plastid homologous recombinant fragments and spetinomycin-resistant aadA gene as select marker. The plasmid p64A was transferred into the chloroplast genome of C. reinhardtii by the biolistic method. Nine independently transformed lines were obtained by 100 mg/L spectinomycin selection. PCR amplification, Southern blot analysis of the transgene and cultivation in the dark all showed that the a-amylase gene had been integrated into chloroplast genome of C. reinhardtii. The activity of amylase expressed in the chloroplast of C. reinhardtii was detected by amylase activity assay and found to be as high as 77.5 u/g fresh weight of cells. These experimental results demonstrated the possibility of using transgenic chloroplasts of plant as bioreactors for production of industrial enzymes.
Chlamydomonas reinhardtii ; genetics ; Chloroplasts ; genetics ; Enzyme Stability ; Plasmids ; Polymerase Chain Reaction ; Pyrococcus furiosus ; enzymology ; alpha-Amylases ; chemistry ; genetics ; metabolism

OBJECTIVETo evaluate the stress level during parachuting training by salivary biomarker and to study the dynamic characteristics.

METHODSTwenty recruits of military parachuting training completed 8 trainings in a month. The saliva samples were collected at 2 h and 1h before boarding and at 0.5 h after landing on the 1st, 4th and 7th trainings. The levels of cortisol, chromogranin A and α-amylase in saliva samples were detected.

RESULTSThe concentrations of cortisol, chromogranin A and activity of α-amylase increased significantly from pre-boarding to landing during 3 trainings. The concentrations of cortisol, chromogranin A and activity of α-amylase at 2 h before boarding and at 0.5 h after landing decreased significantly with the training times. However, the changes of 3 biomarkers at 1 h before boarding among 3 trainings were not significant.

CONCLUSIONThe levels of stress increased significantly for 20 recruits from pre-boarding to landing during parachuting trainings. The stress levels of 20 recruits before boarding and after landing significantly decreased with parachuting training times.

Aviation ; Biomarkers ; analysis ; Chromogranin A ; analysis ; Humans ; Hydrocortisone ; analysis ; Male ; Saliva ; chemistry ; Stress, Psychological ; Young Adult ; alpha-Amylases ; analysis

OBJECTIVEThe present study aimed to test whether exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phone base stations may have effects on salivary alpha-amylase, immunoglobulin A (IgA), and cortisol levels.

METHODSFifty seven participants were randomly allocated to one of three different experimental scenarios (22 participants to scenario 1, 26 to scenario 2, and 9 to scenario 3). Each participant went through five 50-minute exposure sessions. The main RF-EMF source was a GSM-900-MHz antenna located at the outer wall of the building. In scenarios 1 and 2, the first, third, and fifth sessions were "low" (median power flux density 5.2 microW/m(2)) exposure. The second session was "high" (2126.8 microW/m(2)), and the fourth session was "medium" (153.6 microW/m(2)) in scenario 1, and vice versa in scenario 2. Scenario 3 had four "low" exposure conditions, followed by a "high" exposure condition. Biomedical parameters were collected by saliva samples three times a session. Exposure levels were created by shielding curtains.

RESULTSIn scenario 3 from session 4 to session 5 (from "low" to "high" exposure), an increase of cortisol was detected, while in scenarios 1 and 2, a higher concentration of alpha-amylase related to the baseline was identified as compared to that in scenario 3. IgA concentration was not significantly related to the exposure.

CONCLUSIONSRF-EMF in considerably lower field densities than ICNIRP-guidelines may influence certain psychobiological stress markers.

Adolescent ; Adult ; Aged ; Cell Phone ; Female ; Humans ; Hydrocortisone ; analysis ; Immunoglobulin A ; analysis ; Male ; Middle Aged ; Saliva ; chemistry ; Young Adult ; alpha-Amylases ; analysis

OBJECTIVETo investigate and compare the inhibitory properties of free and bound phenolic extracts of clove bud against carbohydrate hydrolyzing enzymes (alpha-amylase & alpha-glucosidase) and Fe(2+)-induced lipid peroxidation in rat pancreas in vitro.

METHODSThe free phenolics were extracted with 80% (v/v) acetone, while bound phenolics were extracted from the alkaline and acid hydrolyzed residue with ethyl acetate. Then, the interaction of the extracts with alpha-amylase and alpha-glucosidase was subsequently assessed. Thereafter, the total phenolic contents and antioxidant activities of the extracts were determined.

RESULTSThe result revealed that both extracts inhibited alpha-amylase and alpha-glucosidase in a dose-dependent manner. However, the alpha-glucosidase inhibitory activity of the extracts were significantly (P<0.05) higher than their alpha-amylase inhibitory activity. The free phenolics (31.67 mg/g) and flavonoid (17.28 mg/g) contents were significantly (P<0.05) higher than bound phenolic (23.52 mg/g) and flavonoid (13.70 mg/g) contents. Both extracts also exhibited high antioxidant activities as typified by their high reducing power, 1,1 diphenyl-2- picrylhydrazyl (DPPH) and 2, 2-azinobis-3-ethylbenzo-thiazoline-6-sulfonate (ABTS) radical scavenging abilities, as well as inhibition of Fe(2+)-induced lipid peroxidation in rat pancreas in vitro.

CONCLUSIONSThis study provides a biochemical rationale by which clove elicits therapeutic effect on type 2 diabetes.

Animals ; Antioxidants ; chemistry ; Carbohydrate Metabolism ; drug effects ; Diabetes Mellitus, Type 2 ; metabolism ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; chemistry ; pharmacology ; Ferrous Compounds ; pharmacology ; Flavonoids ; chemistry ; Glycoside Hydrolase Inhibitors ; chemistry ; pharmacology ; Inhibitory Concentration 50 ; Lipid Peroxidation ; drug effects ; Pancreas ; drug effects ; metabolism ; Phenols ; chemistry ; Plant Extracts ; chemistry ; pharmacology ; Polyphenols ; chemistry ; pharmacology ; Rats ; Syzygium ; chemistry ; alpha-Amylases ; antagonists & inhibitors ; alpha-Glucosidases

OBJECTIVEThe current study was designed to evaluate the various antioxidant potentials and inhibitory effects of phenolic-rich leaf extracts of Bridelia ferruginea (BF) on the in vitro activities of some key enzymes involved in the metabolism of carbohydrates.

METHODSIn this study, BF leaf free and bound phenolic-rich extracts were used. We quantified total phenolic and flavonoid contents, and evaluated several antioxidant activities using assays for ferric reducing antioxidant power, total antioxidant activity (phosphomolybdenum reducing ability), 1,1-diphenyl-2-picrylhydrazyl and thiobarbituric acid reactive species. Also, extracts were tested for their ability to inhibit &alpha;-amylase and &alpha;-glucosidase activity.

RESULTSThe total phenolic and total flavonoid contents in the free phenolic extract of BF were significantly greater than in the bound phenolic extract. Also, all the antioxidant activities considered were significantly greater in the free phenolic extract than in the bound phenolic extract. In the same vein, the free phenolic-rich extract had a significantly higher percentage inhibition against &alpha;-glucosidase activity (IC = 28.5 µg/mL) than the bound phenolic extract (IC = 340.0 µg/mL). On the contrary, the free phenolic extract (IC = 210.0 µg/mL) had significantly lower inhibition against &alpha;-amylase than the bound phenolic-rich extract (IC = 190.0 µg/mL).

CONCLUSIONThe phenolic-rich extracts of BF leaves showed antioxidant potentials and inhibited two key carbohydrate-metabolizing enzymes in vitro.

Animals ; Antioxidants ; chemistry ; pharmacology ; Diabetes Mellitus, Type 2 ; enzymology ; metabolism ; Enzyme Inhibitors ; chemistry ; pharmacology ; Glycoside Hydrolase Inhibitors ; chemistry ; pharmacology ; Humans ; Iron ; adverse effects ; Magnoliopsida ; chemistry ; Oxidative Stress ; drug effects ; Pancreas ; drug effects ; enzymology ; metabolism ; Phenols ; chemistry ; pharmacology ; Plant Extracts ; chemistry ; pharmacology ; Rats ; Swine ; alpha-Amylases ; antagonists & inhibitors ; chemistry ; alpha-Glucosidases ; chemistry