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PubMed2003

Modulation by thyroid hormones of rat parotid amylase secretion stimulated by 5-hydroxytryptamine.

The effects of 5-hydroxytryptamine (5-HT) upon amylase secretion by rat parotid glands were studied in three groups of animals: (a) intact control rats (euthyroid rats); (b) hypothyroid rats obtained by surgical thyroidectomy 2 wk before the experiments; and (c) hyperthyroid rats obtained by the administration of sodium l-triiodothyronine for 2 wk before the experiments. Hyperthyroid rats showed significantly higher baseline amylase release than control rats. When the glands were stimulated with 5-HT (30 micro m), amylase release was significantly lower in the hypothyroid group and higher in the hyperthyroid rats than in control group. Addition of cholinergic, adrenergic or substance P antagonists did not modify 5-HT-stimulated amylase activity. The effects of 5-HT were partly but significantly blocked by the addition of 10 micro m methysergide (HT1/2/7 receptor blocker) in the three groups of rats. In contrast, 10 micro m ketanserine (HT2A receptor blocker) partly blocked the response to 5-HT only in the hyperthyroid animals. It was concluded that 5-HT induces amylase secretion by rat parotid glands through specific serotoninergic receptors, and that thyroid status modulates the 5-HT effect.

Amylases↗
PubMed2007

Enhancement of acid amylase production by an isolated Aspergillus awamori.

AIMS: Evaluation of the influence of fermentation components on extracellular acid amylase production by an isolated fungal strain Aspergillus awamori. METHODS AND RESULTS: Eight fungal metabolic influential factors, viz. soluble starch, corn steep liquor (CSL), casein, potassium dihydrogen phosphate (KH(2)PO(4)) and magnesium sulfate (MgSO(4) x 7H(2)O), pH, temperature and inoculum level were selected to optimize amylase production by A. awamori using fractional factorial design of Taguchi methodology. Significant improvement in acid amylase enzyme production (48%) was achieved. The optimized medium composition consisted of soluble starch--3%; CSL--0.5%; KH(2)PO(4)--0.125%; MgSO(4) x 7H(2)O--0.125%; casein--1.5% at pH 4.0 and temperature at 31 degrees C. CONCLUSION: Optimization of the components of the fermentation medium was carried out using fractional factorial design of Taguchi's L-18 orthogonal array. Based on the influence of interaction components of fermentation, these could be classified as the least significant and the most significant at individual and interaction levels. Least significant factors of individual level have higher interaction severity index and vice versa at enzyme production in this fungal strain. The pH of the medium and substrate (soluble starch) showed maximum production impact (60%) at optimized environment. Temperature and CSL were the least influential factors for acid amylase production. SIGNIFICANCE AND IMPACT OF THE STUDY: Acid amylase production by isolated A. awamori is influenced by the interaction of fermentation factors with fungal metabolism at individual and interaction levels. The pH of the fermentation medium and substrate concentration regulates maximum enzyme production process in this fungal strain.

Amylases↗
PubMed1992

Amylase-producing IgD-type multiple myeloma.

We describe the case of a 63-year-old woman with an IgD-type multiple myeloma and hyperamylasaemia. The evolution of the amylase concentration, the immunohistochemical data and the intracellular amylase contents of the plasma cell were consistent with secretion of amylase by the malignant clone. Moreover, cytogenetic analysis of the bone marrow revealed two structural rearrangements involving chromosome 1 near the amylase locus. Multiple myeloma should be added to the amylase-secreting tumours. This rare entity is not confined to Japan, where it was first recognized.

Adrenal Cortex Hormones↗
PubMed1992

Reciprocal expression of c-jun, proline-rich protein and amylase genes during rat parotid salivary gland development.

We have investigated the temporal expression and cellular localization of the c-jun proto-oncogene and two major rat parotid gland secretory protein genes, PRP (proline-rich protein) and amylase, during postnatal development. c-jun mRNA steady-state levels increased at days 1, 7 and 14 after birth and decreased to basal levels at 21 days and older. PRP mRNA was first detected at 14 days and abruptly increased to adult levels at day 21. Amylase transcripts were first seen at day 7 and progressively increased to adult levels by 28 days. In situ hybridization demonstrated c-jun mRNA accumulation in the differentiating acinar cells and the ducts. The c-jun mRNA accumulation with time corresponds with the proliferative activity reported to occur in these two cellular populations. PRP transcripts were present exclusively in the well differentiated acinar cells while the accumulation of amylase mRNA corresponded to the progressive commitment of parotid cells to acinar differentiation. Our data suggest that during the postnatal development of the rat parotid gland: (a) c-jun expression associates with parotid gland proliferation and precedes the expression of PRP and amylase genes, and (b) activation of PRP and amylase genes is not concomitant and apparently occurs only in differentiating acinar cells.

Age Factors↗
PubMed1984

Dietary regulation of levels of active mRNA coding for amylase and serine protease zymogens in the rat pancreas.

The mechanism by which changes in diet mediate levels of exportable enzymes and proenzymes in pancreatic tissue were studied in rats. The relative levels of mRNA coding for pancreatic amylase, lipase, procarboxypeptidases A and B, and the family of serine protease zymogens have been determined by the ability of isolated RNA to direct the synthesis of these products in a high-fidelity micrococcal nuclease-treated reticulocyte-lysate translation system. Translation products synthesized in vitro correlated directly with products synthesized in vivo in pancreatic lobules. Dietary adaptation was observed when dietary carbohydrate was increased from 0 to 58% at the expense of protein (81-23%). The increase in dietary carbohydrate over this range resulted in a 2-fold increase in amylase synthesis in pancreatic lobules and a 1.8-fold increase in mRNA-directed synthesis of amylase in the translation system in vitro. Concomitant with the decrease in dietary protein, synthesis of serine protease zymogens in pancreatic lobules and in the system in vitro decreased by approximately 50%. Over this range of dietary manipulation, ratios of amylase to serine proteases showed a 3.6-fold change. When dietary carbohydrate was further increased to 81% and protein reduced to 0, non-adaptive changes were observed since there was a decrease in amylase synthesis under conditions both in vivo and in vitro. mRNAs coding for pancreatic lipase and procarboxypeptidases A and B were unaffected by the dietary changes. These findings indicate that nutritional regulation in the tissue levels of pancreatic enzymes and proenzymes is mediated by changes in the content of active cytoplasmic mRNAs.

Amylases↗
PubMed1984

Isolation and the 5'-end nucleotide sequence of Bacillus licheniformis alpha-amylase gene.

We have isolated and determined the 5'-end nucleotide sequence of the alpha-amylase gene from Bacillus licheniformis ATCC 14580. The alpha-amylase produced by this strain is thermostable and of liquefying type. The gene was originally cloned in a bacteriophage lambda 1059 vector. A subclone containing a 5.3 X 10(3)-base insert in pBR322 was further characterized. The nucleotide sequence coding for the 5' end of the structural gene together with the sequence coding for the upstream control regions was determined. The deduced N-terminal amino acid sequence was identical with the previously published amino acid sequence of B. licheniformis alpha-amylase. There was also very strong homology to the N-terminal sequence of Bacillus amyloliquefaciens alpha-amylase. The Mr of the thermostable alpha-amylase, as determined in vitro in a cell-free transcription/translation system of Escherichia coli, was about 55 000.

Amino Acid Sequence↗
PubMed1987

Purification and characterization of extracellular alpha-amylase and glucoamylase from the yeast Candida antarctica CBS 6678.

An alpha-amylase and a glucoamylase were purified to homogeneity from the culture fluid of beta-cyclodextrin-grown Candida antarctica CBS 6678 by protamine sulfate treatment, ammonium sulfate precipitation, gel filtration (Sephadex G-75 sf, Ultrogel AcA 54), DEAE-Sephacel chromatography, hydroxyapatite chromatography and affinity chromatography on acarbose--AH-Sepharose 4B. Both enzymes were monomeric glycoproteins with fairly different amino acid compositions. Their apparent relative molecular mass, sedimentation coefficient (Szero20,w), isoelectric point, absorption coefficient (280 nm), pH and temperature optima were estimated as 48,500, 4.7 S, 10.1, 1.74 cm2 mg-1, 4.2 and 57 degrees C, respectively, for glucoamylase and as 50,000, 4.9 S, 10.3, 1.53 cm2 mg-1, 4.2 and 62 degrees C, respectively, for alpha-amylase. Kinetic analyses indicated that both enzymes preferentially hydrolyzed high-molecular-mass substrates, including some raw starches. alpha-Amylase was active on cyclodextrins, whereas debranching activity was demonstrated for glucoamylase. Trestatins were potent inhibitors of both alpha-amylase (Ki less than 1 microM) and glucoamylase (Ki less than 0.1 microM), being more effective than Bay e 4609 (Ki less than 10 microM). Glucoamylase was selectivity and strongly inhibited by acarbose (Ki less than 0.1 microM). Activity of the latter enzyme was also affected by 1-deoxynojirimycin (Ki less than 1 mM), maltitol and amino alcohols (Ki less than 10 mM). Unlike alpha-amylase, glucoamylase adsorbed strongly onto raw starch, the adsorption site being non-identical with the active site.

Adsorption↗
PubMed1988

Cloning and nucleotide sequence of a heat-stable amylase gene from an anaerobic thermophile, Dictyoglomus thermophilum.

A highly heat-stable amylase gene from an obligately anaerobic and extremely thermophilic bacterium, Dictyoglomus thermophilum, was cloned and expressed in Escherichia coli. The nucleotide sequence of the amylase gene predicts a 686-amino-acid protein of relative molecular mass 81,200, which is consistent with that determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis of the purified enzyme. The NH2-terminal sequence determined using the enzyme purified from E. coli cells corresponds precisely to that predicted from the nucleotide sequence, except for the absence of the NH2-terminal methionine in the mature protein. When the amylase gene was expressed in E. coli cells, the enzyme was localized in the cytoplasmic fraction; this is probably explained by the absence of the signal sequence for secretion. By using the amylase purified from the E. coli transformant, some enzymatic properties, such as optimum pH, optimum temperature, pH-stability and heat-stability, were examined. The amylase was found to be a highly liquefying-type.

Amino Acid Sequence↗
PubMed1988

Cloning and expression in Escherichia coli of two additional amylase genes of a strictly anaerobic thermophile, Dictyoglomus thermophilum, and their nucleotide sequences with extremely low guanine-plus-cytosine contents.

An obligately anaerobic and extremely thermophilic bacterium, Dictyoglomus thermophilum, produces multiple extracellular amylases. In addition to one of the amylase genes, amyA, which we previously cloned and characterized, we have cloned two additional genes, amyB and amyC, coding for amylases of this thermophile, into Escherichia coli and determined their nucleotide sequences. The two amylase genes were expressed under the control of E. coli promoters. Almost all activity was detected in the intracellular fraction in the E. coli cells. The molecular mass and NH2-terminal amino acid sequence of the AmyB enzyme, which was purified from an E. coli transformant containing the amyB gene, confirmed that the reading frame of amyB consisted of 562 amino acids (Mr 67,000). The molecular mass of the AmyC enzyme, estimated by activity staining of a crude extract of E. coli containing amyC, confirmed that AmyC consisted of 498 amino acids (Mr 59,000). The optimal temperatures for AmyB and AmyC activities on soluble starch were 80 degrees C and 70 degrees C, respectively. Both AmyB and AmyC showed a pH optimum of 5.5. AmyB and AmyC showed a different pattern of starch hydrolysis when examined by thin-layer chromatography. Some homology in the amino acid sequences with the functional regions of Taka-amylase A was found in both AmyB and AmyC. The codon usage in the amyA, amyB and amyC genes was highly biased, which reflects the fact that the guanine-plus-cytosine (G + C) content of DNA of D. thermophilum is 29 mol%. The distribution of G and C at each position of the codons was non-random; the G + C content of the first position of codons is significantly high, whereas that of the third position is somewhat low. In addition, codons consisting only of A and T were preferentially used in this thermophile.

Amino Acid Sequence↗
PubMed1993

Sweet potato beta-amylase. Primary structure and identification of the active-site glutamyl residue.

The complete amino acid sequence of a subunit of sweet potato beta-amylase, a homotetramer, was established by sequence analysis of peptides obtained by digestions with Achromobacter protease I and Staphylococcus aureus V8 protease and by cyanogen bromide cleavage of the S-carboxymethylated subunit. The subunit of the enzyme is a single polypeptide consisting of 498 amino acid residues. It showed 50-60% identity in the amino acid sequence with those of beta-amylases from soybean and barley, while it about 25% with those of three bacterial beta-amylases deduced from the cDNA sequences. Sweet potato beta-amylase was completely inactivated with 2,3-epoxypropyl alpha-D-[U-14C]glucopyranoside. Sequence analysis of the inactivated enzyme revealed that Glu187 was specifically esterified by the affinity labeling with the above reagent, proposing that Glu187 is a potent candidate involved directly in the catalysis with this plant beta-amylase.

Amino Acid Sequence↗
PubMed1995

Substrate specificity and detailed characterization of a bifunctional amylase-pullulanase enzyme from Bacillus circulans F-2 having two different active sites on one polypeptide.

Bacillus circulans F-2 amylase-pullulanase enzyme (APE) displayed dual activity with respect to glycosidic bond cleavage. The enzyme was active on alpha-1,6 bonds in pullulan, amylopectin, and glycogen, while it showed alpha-1,4 activity against malto-oligosaccharides, amylose, amylopectin, and soluble starch, but not pullulan. Kinetic analysis of the purified enzyme in a system which contained both pullulan and amylose as two competing substrates was used to distinguish the dual specificity of the enzyme from the single-substrate specificity known for pullulanases and alpha-amylases. Enzyme activities were inhibited by some metal ions, and by metal-chelating agents with a different mode. The enzyme-inhibitory results of amylase and pullulanase with Hg2+ and Co2+ ions were different, indicating that the activation mechanisms of both enzyme activities are different. Cyclomaltoheptaose inhibited both alpha-amylase and pullulanase activities with inhibition constants (Ki) of 0.029 and 0.06 mg/ml, respectively. Modification with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide confirmed a carboxy group at the active sites of both enzymes. The N-terminal sequence of the enzyme was: Ala-Asp-Ala-Lys-Lys-Thr-Pro- Gln-Gln-Gln-Phe- Asp-Ala-Leu-Trp-Ala-Ala-Gly-Ile-Val-Thr-Gly-Thr-Pro-Asp-Gly-Phe. The purified enzyme displayed Michaelis constant (Km) values of 0.55 mg/ml for amylose, and 0.71 mg/ml for pullulan. When both amylose and pullulan were simultaneously present, the observed rate of product formation closely fitted a kinetic model in which the two substrates are hydrolyzed at different active sites. These results suggest that amylopullulanases, which possess both alpha-1,6 and alpha-1,4 cleavage activities at the same active site, should be distinguished from APEs, which contain both activities at different active sites on the same polypeptide. Also, it is proposed that the Enzyme Commission use the term 'amylase-pullulanase enzyme' to refer to enzymes which act on starch and cleave both alpha-1,6-bonds in pullulan and alpha-1,4 bonds in amylose at different active sites.

Amino Acid Sequence↗
PubMed1984

Serum amylase, isoamylase and lipase in acute alcoholism.

Hyperamylasemia is found in asymptomatic alcoholics. The aim of this study was to document the incidence of elevations of serum amylase and lipase in asymptomatic alcoholics and to evaluate the contribution of salivary isoamylase to the total serum amylase. One hundred and three patients with acute alcohol withdrawal were studied. Total serum amylase was elevated in 7 patients (6.8%) of whom 4 (57%) showed elevation of salivary isoamylase. Elevated lipase levels were found in 11 patients (10.7%) but correlation of lipase levels with either amylase or isoamylase levels was poor. Thus there was a low but significant incidence of hyperamylasemia which resulted from an elevated salivary isoamylase in the majority of cases. Lipase determination did not assist in defining the origin of the hyperamylasemia and correlated poorly with the other enzymes. It is probably more sensitive than amylase in reflecting the toxic effects of alcohol on the pancreas.

Adult↗
PubMed1982

Dissociation of beta-adrenoceptor-induced effects on amylase secretion and cyclic adenosine 3', 5' monophosphate accumulation.

By using a multi-channel microperifusion system the effects of noradrenaline, the beta1-adrenoceptor agonist prenalterol, and the beta2-selective agonist terbutaline were studied on amylase pig submandibular glands. 2 Noradrenaline caused significant amylase discharge and cyclic AMP accumulation. 3 Prenalterol was as effective as noradrenaline in causing amylase release but did not significantly affect the cyclic AMP content. 4 Terbutaline stimulated cyclic AMP accumulation, but had little effect on amylase secretion. 5 The present study reveals that there is a dissociation of the beta-adrenoceptor-induced amylase release and cyclic AMP formation, and that this dissociation may be due to different beta-adrenoceptor subtypes.

Amylases↗
PubMed1999

Serum amylase measured four hours after endoscopic sphincterotomy is a reliable predictor of postprocedure pancreatitis.

OBJECTIVE: Acute pancreatitis is a common complication after endoscopic sphincterotomy (ES) and endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to detect the time when the peak of serum amylase was predictive for pancreatitis or severe hyperamylasemia, to plan a prolonged follow-up in the hospital and for outpatients. METHODS: In a prospective series of 409 consecutive patients undergoing ES, serum amylase activity was measured immediately before the procedure and 2, 4, 8, and 24 h thereafter; the data obtained at 2, 4, and 8 h were compared with those at 24 h and with the outcome. Sensitivity for long-lasting severe hyperamylasemia (more than five times the upper normal limit) and pancreatitis were also defined for all sampling times. RESULTS: At 24 h after ES, amylase was still more than five times the upper normal limit in 26 patients, 19 of whom had mild/moderate acute pancreatitis. There was a significant difference (p < 0.01 at all sampling times) between the 26 patients with 24-h severe hyperamylasemia and those with lower levels. The sensitivity of amylase measurement in detecting pancreatitis or long-lasting severe hyperamylasemia was highest at 8 h. However, the 4-h assessment appears to be a reliable predictor in practice, as more than two-thirds of cases of pancreatitis (all but one with computed tomography-confirmed pancreatitis) occurred among patients whose 4-h amylasemia was higher than five times the upper normal limit. CONCLUSIONS: Serum amylase assessment 4 h after ES minimizes the likelihood of underestimating the risk of postprocedure pancreatitis. It is therefore a reliable, cost-effective follow-up, particularly in outpatients.

Acute Disease↗
PubMed2001

Serum amylase and lipase activities in normal pregnancy: a prospective case-control study.

OBJECTIVE: The diagnosis of acute pancreatitis during pregnancy is usually based on the association of upper abdominal pain, nausea or vomiting, and elevated serum amylase or lipase activities. The changes in these enzymatic activities have not been clearly established during normal pregnancy. The aim of this study was therefore to evaluate serum amylase and lipase activities in healthy pregnant women. METHODS: Serum amylase and lipase activities were measured in 103 pregnant women (first trimester, n = 34; second trimester, n = 36; third trimester, n = 33) and in 103 nonpregnant women matched for age and not receiving oral contraception. RESULTS: Serum amylase activity was similar in pregnant women and nonpregnant women during all trimesters of pregnancy. Serum lipase activity was significantly lower during the first trimester of pregnancy compared to nonpregnant women (48.6+/-27.6 vs 59.2+/-29.3 IU/L, p < 0.05) and compared to the third trimester (48.6+/-27.6 vs 76.3+/-35.8 IU/L, p < 0.001). Serum lipase activity was not statistically different between pregnant and nonpregnant women during the second and third trimesters. CONCLUSION: An increase in serum amylase and lipase activities during pregnancy should be taken into account, as in nonpregnant women.

Adult↗
PubMed1990

Nucleotide sequence of the G6-amylase gene from alkalophilic Bacillus sp. H-167.

The nucleotide sequence of the G6-amylase gene from alkalophilic Bacillus sp. H-167 was determined. The open reading frame of the gene consisted of 2865 base pairs, encoding 955 amino acids. The NH2-terminal amino acid sequence analysis of the G6-amylase indicated that the enzyme had a single peptide of 33 amino acid residues and the mature enzyme was composed of 922 amino acids, giving a molecular mass of 102,598. Identity of the NH2-terminal amino acid sequences among each component of the multiform G6-amylase suggested the proteolytic processing of the COOH-terminal side of the enzyme. The DNA sequence and the deduced amino acid sequence of the G6-amylase gene showed no homology with those of other bacterial alpha-amylases although the consensus amino acid sequences of the active center were well conserved.

Amino Acid Sequence↗
PubMed1982

Degeneration secretion of amylase from the parotid gland of the rat.

In anaesthetized rats the parotid saliva secreted during degeneration of the auriculo-temporal nerve contains amylase in fairly constant concentration, the amylase output varying with the secretory rate. The amount of amylase was not reduced by adrenoceptor blocking agents; it was increased by sympathectomy carried out one week in advance. A sympathetic degeneration secretion of amylase could also be demonstrated while the post-ganglionic sympathetic nerves were degenerating; a simultaneous parasympathetic degeneration secretion provided the salivary flow needed for the transport of the amylase.

Amylases↗
PubMed1973

Amylase secretion by the perfused cat pancreas in relation to the secretion of calcium and other electrolytes and as influenced by the external ionic environment.

1. Amylase secretion from the perfused pancreas consists of two components: a small continuous basal secretion and a stimulated secretion in response to acetylcholine or cholecystokinin-pancreozymin. The response to small doses of either stimulant was repeatable over several hours.2. The calcium concentration of pancreatic juice, always less than that of the perfusate, was normally constant above secretory rates of 0.15 g/10 min. However, when the concentration of enzymes in the juice rose, either after stimulation or at very low secretory rates, the calcium concentration rose in parallel, suggesting that this calcium is bound to, or is a component of, pancreatic enzymes.3. Elevation of the perfusate calcium concentration resulted in a parallel increase in the calcium concentration of the pancreatic juice.4. Calcium-free solutions initially caused a small reduction in basal and stimulated amylase secretion and, after prolonged periods of perfusion, abolished stimulated secretion and caused a reduction in electrolyte secretion. The latter was completely reversed by calcium-rich perfusates but the effects on enzyme secretion were only partially reversible.5. Calcium-rich perfusates had no effect on the rate of electrolyte secretion but potentiated submaximally stimulated amylase secretion.6. Barium did not substitute for calcium in supporting pancreatic secretion.7. Alterations in the extracellular concentrations of sodium, potassium and magnesium had no direct effect on amylase secretion.8. The local anaesthetic tetracaine inhibited amylase secretion at a lower concentration than that required to inhibit electrolyte secretion.9. It is concluded (a) that calcium is secreted into the pancreatic juice in two fractions, one associated with enzymes and the other with the electrolyte component of the juice; and (b) that calcium ions play an important role in the stimulus-secretion coupling of pancreatic acinar cells, but that the effects of calcium depletion on electrolyte secretion may principally be due to alterations in the permeability of the duct system.

Acetylcholine↗