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PubMed1993

Alpha-amylase immobilized on plastic supports: stabilities, pH and temperature profiles and kinetic parameters.

The covalent immobilization of alpha-amylase on new isocyanate, acid chloride and carboxylic acid--activated plastic supports shows the viability of such supports for immobilizing enzymes, especially those reacting with 1,6-diaminohexane and glutaraldehyde for producing side arms. The operational stability of immobilized alpha-amylase could be extended by crosslinking the enzyme or by extending the support's side arm (substrate concentration has no effect). Inactive immobilized alpha-amylase were unfolded and then refolded at elevated temperature, these supports were found to be essential in increasing the stability of the enzyme during refolding. The pH curves for the immobilized enzyme were in general found not to be shifted from the soluble enzyme's pH optimum, although one isocyanate plastic support derivative shifted the pH activity profile of alpha-amylase to a higher range by 1.5 pH units, probably due to reaction between the enzyme and the free anhydride groups existing on the support's surface. In all cases, the immobilized enzyme's temperature activity profiles were shifted to a lower temperature range when compared to the soluble enzyme. The immobilized alpha-amylase Michaelis constants increased and the the maximum rates and specific activities decreased when compared to the soluble enzyme kinetic parameters.

Bacillus subtilis↗
PubMed2005

Effects of dietary alpha-amylase on metabolism and performance of transition dairy cows.

Twenty-four multiparous Holstein cows [body weight, 759 kg (SD = 30 kg); body condition score, 3.2 (SD = 0.13)] were used in a randomized complete block design to determine the effect of feeding alpha-amylase during the transition period on rumen fermentation, key metabolic indicators, and lactation performance. Cows were assigned to either a control diet or the control diet supplemented with alpha-amylase (662 fungal amylase units per gram, AMA) at 0.1% of diet dry matter (DM). Experimental diets were fed from 21 d before expected calving through 21 d in milk. From 22 to 70 d in milk, all cows were fed a similar lactation cow diet. Average pre- and postpartum DM intakes were 12.4 and 17.8 kg/d, respectively, and did not differ between treatments; however, DM intakes during the last week prepartum decreased to a greater degree in AMA than control cows compared with wk -2. Supplementing diets with alpha-amylase tended to increase proportions of ruminal butyrate prepartum but not postpartum. Treatment differences were not detected for concentrations of insulin in plasma and lipid and glycogen in liver tissue. Prepartum, concentrations of beta-hydroxybutyrate and nonesterified fatty acids were increased in cows fed AMA compared with the control diet. Postpartum, concentrations of glucose in plasma tended to be increased by feeding AMA. Increased plasma beta-hydroxybutyrate and nonesterified fatty acids pre- but not postpartum and a tendency for increased plasma glucose postpartum demonstrate shifting reliance from lipid- to carbohydrate-based metabolism postpartum in cows fed alpha-amylase.

3-Hydroxybutyric Acid↗
PubMed1989

In vivo action of alpha-amylase inhibitor from cranberry bean (Phaseolus vulgaris) in rat small intestine.

An alpha-amylase inhibitor prepared from cranberry bean (Phaseolus vulgaris) was examined for its in vivo action on pancreatic alpha-amylase in rat small intestine. For this purpose, postprandial changes not only in intraluminal alpha-amylase activity but also in plasma glucose and insulin concentrations were measured at various times after administration of 2 g of 10% polyethylene glycol-containing experimental diets with and without the inhibitor. No considerable increase was observed in the levels of intraluminal alpha-amylase activity, blood sugar, and plasma insulin in the animals given the inhibitor at a dose of 10 mg each. These results suggest that the purified preparation from cranberry bean serves in fact as a potent inhibitor of rat pancreatic alpha-amylase.

Animals↗
PubMed1998

Trienzyme treatment for food folate analysis: optimal pH and incubation time for alpha-amylase and protease treatment.

Recent reports have indicated that trienzyme treatment before folate determination is essential to obtain the proper folate content in foods. Trienzyme treatment is performed by using alpha-amylase and protease for folate extraction from carbohydrate and protein matrices, and folate conjugase for the hydrolysis of polyglutamyl folates. We evaluated the conditions of pH and incubation time for the treatment with alpha-amylase and protease. Four food items, including fresh beef, white bread, cow's milk, and fresh spinach, were selected for this investigation. We found that optimal pHs for alpha-amylase treatment of beef and cow's milk were 7.0 and 5.0, respectively, whereas those for white bread and spinach were not distinctive at pHs from 2.0 to 7.0. The optimal incubation time for alpha-amylase was 4 h for fresh beef and cow's milk, whereas no distinctive optimal incubation period was found for white bread and fresh spinach. Our data indicate that the conditions for enzyme treatments vary depending on food items. Trienzyme treatment resulted in an increase of more than 50% in the mean folate content over folate conjugase treatment alone. It is necessary to treat food samples with not only traditional folate conjugase, but also with alpha-amylase and protease before folate determination to obtain the actual folate content.

Animals↗
PubMed1975

Circulatory turnover of pancreatic amylase.

Radiolabeled amylase and unlabeled pancreatic amylase were infused into pigs in order to determine the plasma half-life of the enzyme. Regardless of the parameter measured (radioactivity, enzyme activity or concentration), the plasma removal curves could be resolved into three components when subjected to tracer analysis. The plasma half-life was estimated to be approximately 3 hr. Through the use of a recently developed radioimmunoassay specific for porcine pancreatic amylase, the plasma concentration of amylase was calculated at 2.4 mug/ml. Knowing the plasma concentration and half-life of amylase we determined the circulatory turnover of the enzyme. Over a 2.4-hr period, 9.6 mug of pancreatic amylase/ml of plasma must re-enter the circulation to maintain the enzyme at constant levels.

Amylases↗
PubMed1993

Pancreatic splenic lobe organ culture system: viability and amylase release.

An organ explant culture system for the intact chick pancreatic splenic lobe (SL) was characterized for exocrine function. Organ cultures were prepared using the pancreatic splenic lobe from 9- and 15-day-old male broiler chicks (Arbor Acres x Arbor Acres) to characterize amylase release as well as tissue integrity during 2, 4, 8, and 12 h of incubation. Light microscopy studies indicated necrosis of the exocrine pancreatic acini after 4 h of incubation. Changes in islets of Langerhans were noted 4 h after incubation, but islet structural integrity remained intact for up to 12 h of incubation. Lactate dehydrogenase (LD) levels measured in the culture medium did not increase significantly from 2 to 4 h of incubation. After 4 h of incubation, total LD levels increased (P < .05) for the 9-day-old SL cultures, and LD levels increased (P < .01) per unit weight of SL for the 15-day-old cultures. Medium amylase activity did not increase after 2 h of incubation. Large increases occurred for total amylase activity and amylase activity per unit weight of SL between 4 and 12 h of incubation for both 9- and 15-day-old cultures. Histological examination as well as increases in LD and amylase activities for total and per unit weight of SL in the incubation medium suggest that the viability of the 9- and 15-day-old SL organ incubation system decreases after 4 h.

Aging↗
PubMed1976

Mucoviscidosis: total amylase activity of serum and mixed saliva in homozygous and heterozygous subjects.

Total amylase activity of serum and mixed saliva was studied in homozygotes and heterozygotes for mucoviscidosis and in healthy subjects. Mean serum total activity was 269.0 +/- 113.7 U/l in the homozygotes, exceeding in nearly 50% of the cases the values given in the literature and those observed in the normal controls. The difference against the control group was significant (P less than 0.05). Mean serum total amylase activity of heterozygotes agreed with the mean value for the healthy group (203.5 +/- 79.5 U/l) without a significant difference. Total amylase activity in the saliva of homozygotes (148.700 +/- 65.700 U/l) was higher than in the heterozygotes /118.300 +/- 74.200 U/l) of the healthy children (51.700 +/- 26.500 U/l). The difference between the homozygous and healthy groups was strongly significant (P less than 0.01), and that between the heterozygous group and the combined healthy children and adult groups was also significant (P less than 0.05). In the heterozygotes, salivary amylase activity was slightly elevated but not significantly different from the control group and did not result in a change in serum total amylase activity.

Adult↗
PubMed1999

High level production of thermostable alpha-amylase from Sulfolobus solfataricus in high-cell density culture of the food yeast Candida utilis.

The alpha-amylase from Sulfolobus solfataricus has the commercially important ability to hydrolyze glycosyltrehalose and can be used for the production of trehalose from soluble starch. We have produced this enzyme in the food yeast Candida utilis at extremely high levels. Because the S. solfataricus gene was previously shown to be very poorly expressed, the gene was resynthesized based on codons preferentially found in the highly expressed C. utilis glyceraldehyde-3-phosphate dehydrogenase (GAP) gene. Expression of this synthetic gene under the control of the GAP promoter yielded biologically active alpha-amylase, accounting for more than 50% of the soluble protein. Comparison of the expression levels of various chimeric constructs of the synthetic and native genes indicated that the production level of the alpha-amylase was improved more than 2x10(4)-fold by substituting the native gene with the synthesized one. Northern analysis revealed the formation of short mRNAs in transformants with constructs containing native gene fragments, suggesting that premature termination of the transcripts is responsible for the low production level. The alpha-amylase-producing C. utilis cells were grown up to 92 grams dry cell weight per liter in a synthetic medium, yielding 12.3 g/l alpha-amylase which accounts for up to 27% of total cell proteins.

Amino Acid Sequence↗
PubMed2000

Calcium-mediated conversion of sucrose to starch in relation to the activities of amylases and sucrose-metabolizing enzymes in sorghum grains raised through liquid culture.

Detached ears of sorghum (Sorghum vulgare) were cultured in complete liquid medium containing Ca2+(0, 3, 10 and 30 mM) and effect of this ion on the conversion of sucrose to starch with respect to the activities of amylases, sucrose synthase, sucrose phosphate synthase and soluble invertases were studied in developing grains. Presence of 3 mM Ca2+ in culture medium enhanced both accumulation of starch and activity of alpha-amylase in grain but without having any influence on the activity of beta-amylase. However, with 10 and 30 mM Ca2+, the accumulation of starch and activities of both amylases decreased and with advancement in culturing period, starch accumulation was further decreased. Irrespective of its concentration, Ca2+ enhanced the activities of sucrose synthase (synthesis), sucrose-phosphate synthase, soluble acid invertase and soluble-neutral invertase. Increase in the concentration of Ca2+ in culture medium was concomitant with an elevation in relative proportion of sucrose in the grain reflecting a net balance in per cent increase with Ca2+ in the activities of sucrose-synthesizing enzymes over sucrose-hydrolysing ones. Based on the results, it is suggested that assimilation of Ca2+ by grain is essential for maintaining high activity of alpha-amylase to generate starch primers required for the conversion of sucrose to starch during grain filling in sorghum.

Amylases↗
PubMed1975

Comparison of human pancreatic and parotid amylase activities on different substrates.

The specific activities of highly purified preparations of human parotid and pancreatic amylase on several different soluble and insoluble starches were compared. The ratio of parotid to pancreatic activity varied with the physical nature of the substrate. With all soluble starches, irrespective of source, parotid amylase exhibited a higher specific activity than did pancreatic amylase; the reverse was true for an insoluble chromogenic starch (Amylose Azure). The variation in enzyme-substrate interaction supports previous indications of configurational differences between the two amylases. The observed organ-specific characteristics according to organ of origin may have value in determining relative parotid and pancreatic amylase activities in body fluids under normal and pathological conditions, thereby helping to clarify their functional and clinical significance.

Amylases↗
PubMed2000

Bacterial amylolytic activity enhances beta-glucuronidase expression of amylase-negative Escherichia coli strain in starch-medium.

The possibility of associating starch degradation with bacterial beta-glucuronidase expression was examined. We proved that starving, in starch medium, amylase-negative Escherichia coli (M94) which has constitutive beta-glucuronidase greatly reduces (p < 0.01) its background activity, but the addition of both cell-free supernatants or cells of Bacillus subtilis (B10) producing amylase greatly increases (p < 0.01) the E. coli beta-glucuronidase activity. Increases in activity were maximal when amylase in the medium ranged from 0.3 to 0.8 U ml-1 and pH from 6.8 to 6.3, whereas higher amylase activity interacted with E. coli viability and the effect on beta-glucuronidase was less evident. The impact of B. subtilis amylase on E. coli beta-glucuronidase induction, observed when the organisms were co-cultured, indirectly supports the hypothesis that amylolytic activity of hindgut bacteria may be effective on beta-glucuronidase induction of the climax microflora. This last finding is important in the health field, considering the implication between the deconjugating role of this enzyme and consequent activation of toxic and carcinogenic compounds.

Amylases↗
PubMed2001

Serum amylase and lipase elevation is associated with intracranial events.

Serum amylase and lipase elevation has been observed in trauma patients and patients with traumatic intracranial bleeding. However, the causes of this elevation have not been clearly elucidated. A further question remains as to whether other intracranial events are associated with such enzyme elevation as well. We retrospectively reviewed 75 patients consecutively admitted to Cook County Hospital Neurosurgical Intensive Care Unit over a 3-month period for trauma, infection, tumor, or other space-occupying lesions with an unstable condition or neurological deficit. Eleven patients (15%) had elevated amylase and lipase levels. The patients were divided into two groups: Group I (n = 64) had normal and Group II (n = 11) had raised amylase and lipase levels [amylase 402 +/- 444 U/L with normal < or = 125 U/L and lipase 474 +/- 313 U/L with normal < or = 55 U/L]. All Group II patients suffered an intracranial event. Twenty-four Group I (38%) and 10 Group II (91%) patients required craniotomy (P < 0.01). No patients had clinical or radiographic evidence of pancreatitis. In summary, intracranial events are associated with serum amylase and lipase elevation probably through centrally activated pathways. Because of the lack of diagnostic value, routine pancreatic enzyme monitoring should not be performed in this patient population.

Aged↗
PubMed2001

[Alpha-amylase/glucose index in amniotic fluid as a new method in prenatal assessment of fetal maturity].

Prenatal diagnosis of amniotic fluid enables fetal maturity evaluation, particularly that of fetal lungs. The aim of the study is to evaluate the diagnostic value of on alpha-amylase/glucose index in amniotic fluid in comparison to routinely performed tests, used for prenatal fetal lung maturity evaluation, particularly in respect of PG concentration, whose predictive value is almost 100%. The study was carried out on 180 pregnant women, chosen by random selection, hospitalized in Polish Mother's Health Centre Hospital in the period from 15.06.1994 to 31.12.1995. 223 samples of amniotic fluid were tested- in all samples following assays and tests were performed: bubble stability test (BST), optical density, orange cells test, phosphatidylglycerol concentration (PG), glucose concentration, alpha-amylase activity urea and creatinine concentration. The alpha-amylase/glucose index in amniotic fluid is statistically significant with PG concentration. The value of the alpha-amylase/glucose index is < 6.0 when amniotic fluid assay indicates fetal immaturity, but when amniotic fluid assay indicates fetal maturity, its value is 36.0. The evaluation of fetal lung maturity on the basis of the alpha-amylase/glucose index multiply decreases the cost of examinations. Authors make a suggestion to implement this method in all hospital departments of the country.

Adolescent↗
PubMed2002

Preferential transcription of a gene for alpha amylase in the carcinoid tumor of African rodent Mastomys natalensis.

The carcinoid tumor in Mastomys natalensis provides a useful animal model of tumorigenesis. We investigated preferentially transcribed genes in this carcinoid tumor by differential hybridization. Fourteen clones corresponding to high levels of transcription were isolated from a cDNA library. Sequencing analysis and a homology search revealed that the clones corresponded to genes for chromogranin and alpha-amylase. High-level transcription of a gene for alpha-amylase gene in Mastomys carcinoid tumor was confirmed by Northern blotting analysis. Furthermore, Western blotting analysis confirmed the expression of alpha-amylase in tumors at the protein level. Immunohistochemical staining revealed alpha-amylase in the cytoplasm of Mastomys carcinoid tumors. Our results demonstrated that an exocrine enzyme 'amylase' could be produced ectopically by a neuroen docrine tumor.

Africa↗
PubMed2002

Insulin enhances amylase and lipase activity in the pancreas of streptozotocin-diabetic rats. An in vivo study.

OBJECTIVE: To analyze the biochemical effect of in vivo insulin therapy on the amylase and lipase activities in the pancreatic acinar cells of streptozotocin-diabetic rats, and to detect any possible regeneration in the beta cells of the islets of Langerhans using transmission electron microscopy. METHODS: Adult male albino Fischer-344 rats were divided into 3 groups, the first group received drug vehicle and served as controls, the 2nd group was made diabetic with a single intravenous dose of streptozotocin (75 mg/kg body weight), while the 3rd group was made diabetic as in its 2nd group but the rats were treated with Lente human insulin. Their body weight, blood glucose and glucosuria were regularly recorded, and blood samples for serum immunoreactive insulin assay were taken from each rat at sacrifice. The largest part of each excised pancreas was homogenized for biochemical assay of amylase, lipase and insulin, while only a small part of the gland was used for morphological survey. The study was conducted in the Faculty of Medicine, University of Jordan, Amman, Jordan. RESULTS: The serum immunoreactive and pancreatic-homogenate insulin levels of the untreated diabetic rats were reduced by 85% and 37% compared with those of the controls. Their pancreatic amylase and lipase levels were also reduced by 66% and 43%. Insulin treatment of diabetic rats resulted in a 65-fold increase in serum immunoreactive insulin, and approximately 61%, 47%, and 25% increase in the pancreatic-homogenate levels of amylase, lipase, and insulin. Electron microscopic examination of the pancreas of untreated and insulin-treated diabetic rats showed no evidence of beta cell regeneration. CONCLUSION: Inspite of the controversies in an extensively studied field of in vivo and in vitro influence of insulin on pancreatic enzymes, our present biochemical data clearly indicates that in vivo insulin administration has a stimulant effect on both amylase and lipase activity in the pancreatic acinar cells of streptozotocin-diabetic rats. It also proposes that insulin might play an important role in beta cell regeneration although no morphological evidence of beta cell mitosis was demonstrable. We finally suggest that the biochemical assay of pancreatic enzymes might be of value in determining the severity and chronicity of human insulin-dependent diabetes, and can be used as a parameter in evaluating the response to treatment.

Amylases↗
PubMed1976

Salivary amylase in duodenal aspirates.

Salivary and pancreatic isoamylases in duodenal aspirates obtained during assessment of pancreatic function after test meal stimulation were separated by agarose gel electrophoresis. Salivary amylase was found to be a constituent of the duodenal aspirates in more than 75% of the tests. The mean relative contribution of salivary amylase to the total amylase activity of the aspirates varied from about 15% in normals to about 40% in patients with chronic pancreatitis and pancreatic carcinoma. The amount of salivary amylase varied widely not only between the individuals but also within the samples of the same test series. Specific determination of the pancreatic isoamylases instead of determination of the total amylase increased the discrimination between normals and patients with pancreatic dysfunction.

Amylases↗
PubMed2000

[Cloning and expression of the gene encoding novel alpha-amylase from Sulfolobus shibatae in E. coli].

A novel alpha-amylase gene was amplified from Sulfolobus shibatae by using PCR technique. The amplified 1.7 kb DNA fragment was inserted into an expression vector pBV220 to yield the recombinant plasmid pSBAM. The novel alpha-amylase gene in pSBAM was expressed in E. coli. The production of the novel alpha-amylase activity reached over 8 units/100 mL of the culture. The molecular weight of this enzyme was about 61 kD by SDS-PAGE. The expressed novel alpha-amylase protein in E. coli DH5 alpha accounted for about 20% of the total protein in the recombinant cell. The cooperative action of the novel alpha-amylase and the maltooligosyltrehalose synthase from Sulfolobus shibatae was investigated and trehalose was detected by using HPLC analysis when using amylose and partial starch hydrolysates as substrates.

Cloning, Molecular↗
PubMedDate not supplied

Effect of fungicides on the production of amylase by Rhizopus oryzae.

Seven fungicides (Brassicol), captan, Dithane M-45, Fytolan, Parasan, Sulfex and Thiram) were tested for their effect on the production of amylase enzyme by Rhizopus oryzae. The activity of amylase was determined by cup-plate method. All the fungicides were found inhibitory for the synthesis of amylase. Out of these, Parasan was the most effective causing hundred percent inhibition at 0.025% concentration. No amylase production was recorded when Thiram, Fytolan, Brassicol, Captan and Dithane M-45 were used at 0.5, 1.5, 2.0, 2.0, and 2.0% concentration respectively. Sulfex was found to be less effective, as hundred percent inhibition of amylase production has not been recorded even at 3.0% concentration.

Amylases↗