Disease relevance of AMY2B

• The crystal structure of the complex formed between the 498 amino acid residue porcine pancreatic alpha-amylase (PPA) and the 74 amino acid residue inhibitor Tendamistat secreted from Streptomyces tendae, has been determined by multiple isomorphous replacement in a crystal of space group P6(5)22 (a = b = 77.7 A, c = 359.5 A) [1].
• The compounds were tested for their antimuscarinic activities by: (a) inhibition of [N-methyl-3H]scopolamine binding to the muscarinic receptors of N4TG1 neuroblastoma cells, (b) inhibition of carbachol-induced alpha-amylase release from rat pancreas acini, and (c) blocking of acetylcholine-induced contraction of guinea pig ileum [2].
• In order to obtain information on their structure, a hepatopancreas cDNA library constructed in phage lambda-Zap II (Strategene) was screened using a synthetic oligonucleotide based on the amino acid sequence of a V8 staphylococcal protease peptide of P. vannamei alpha-amylase [3].
• It was concluded that the minimal adjuvant-active subunit of cell wall peptidoglycan for the induction of delayed-type hypersensitivity to monoazobenzenearsonate-N-acetyl-L-tyrosine and for circulating-antibody formation to bacterial alpha-amylase and the thymus-independent antigen DNP-Ficoll was N-acetylmuramyldipeptide, MurNAc-L-Ala-D-isoGln [4].
• Acid hydrolysis of retrograded amylose gave a resistant fragment having an average d.p. of 32, human-salivary and porcine-pancreatic alpha amylases gave a resistant fragment of d.p. 43, and Bacillus subtilis alpha amylase gave a resistant fragment of d.p. 50 [5].

High impact information on AMY2B

• After immunization of a dromedary with bovine erythrocyte carbonic anhydrase and porcine pancreatic alpha-amylase, it was demonstrated that a considerable amount of heavy-chain antibodies, acting as true competitive inhibitors, circulate in the bloodstream [6].
• Affinity-purified, monospecific rabbit antibodies against rat pancreatic alpha-amylase and bovine pancreatic alpha-chymotrypsinogen were used for immunoferritin observations of ultrathin frozen sections of mildly fixed exocrine pancreatic tissue from secretion-stimulated (pilocarpine) rats and from overnight-fasted rats and guinea pigs [7].
• The most thermostable alpha-amylase from Bacillus licheniformis (apparent transition temperature, T(1/2) approximately 100 degrees C) shows an unfolding rate which is four orders of magnitude smaller as compared with the alpha-amylase from pig pancreas (T(1/2) approximately 65 degrees C) [8].
• Binding with biotin-polymer sugar probes revealed that the alpha-amylase has affinity to alpha-mannose, alpha-N-acetylneuraminic acid, and beta-N-acetyllactosamine, which are components of N-glycans [9].
• 0. A binary complex formation out of equimolar amounts of the inhibitor and alpha-amylase, was demonstrated by polyacrylamide gel electrophoresis, and Bio-Gel P-100 chromatography [10].

Chemical compound and disease context of AMY2B

• The effect of alpha-amylase is detrimental, however, in the disease state diabetes mellitus, where blood glucose levels are elevated due to a biochemical defect [11].
• A fluorescent reagent, o-phthalaldehyde (OPA), competitively inhibited porcine pancreatic alpha-amylase (PPA) with Ki values of 0.7-0.9 mM, while alpha-amylase from Bacillus subtilis (BS) was uncompetitively inhibited, with Ki values of 5.8-7.6 mM [12].

Biological context of AMY2B

• The structural X-ray map of a pig pancreatic alpha-amylase crystal soaked (and flash-frozen) with a maltopentaose substrate showed a pattern of electron density corresponding to the binding of oligosaccharides at the active site and at three surface binding sites [13].
• Kinetics and energetics of ligand binding determined by microcalorimetry: insights into active site mobility in a psychrophilic alpha-amylase [14].
• Refined molecular structure of pig pancreatic alpha-amylase at 2.1 A resolution [15].
• Thus, natural molecular evolution as well as combinatorial evolution selected the same alpha-amylase binding determinants for completely different spatial frameworks [16].
• L-PG showed potent adjuvant activities for circulating antibody formation and development of delayed-type hypersensitivity to bacterial alpha-amylase in vivo and for the primary immune response to sheep erythrocytes in vitro, as well as L-CWS [17].

Anatomical context of AMY2B

• Fractions were analyzed for protein, alpha-amylase (EC 3.2.1.1) and 5'-nucleotidase (EC 3.1.3.5) as marker enzymes for zymogen granule content and membranes, respectively [18].
• In isolated parotid gland lobules alpha-amylase secretion proceeded at a linear rate already during the first 1 min of stimulation, whereas in pancreatic lobules a measurable rate of alpha-amylase secretion did not occur before 5 min [19].
• Only one distinct peak, with coincident alpha-amylase and 5'-nucleotidase activity, and most protein was detected, which reflects the presence of a single population of intact zymogen granules [18].
• Starch granules are digested by pancreatic alpha-amylase in the small intestine [20].
• New allelic variants of salivary gland alpha-amylase in pigs (AMY-1C, AMY-1D) have been detected using affinity electrophoresis [21].

Associations of AMY2B with chemical compounds

• Molecular basis of the effects of chloride ion on the acid-base catalyst in the mechanism of pancreatic alpha-amylase [22].
• When standard alpha-amylase and translation products are subjected to electrophoresis on polyacrylamide gel containing 0.01% starch and CaCl2, active amylase which binds tightly to starch can only migrate as the starch is hydrolyzed [23].
• Its presence explains the multivalency of alpha-amylase binding to dextrins in solution [15].
• A crystalline complex of the pancreatic alpha-amylase with alpha-cyclodextrin, a cyclic substrate analog of six glucose residues, reveals, in difference Fourier maps, three unique binding sites [15].
• Bovine pancreatic alpha-amylase binds 1 mol of acarbose (a carbohydrate alpha-amylase inhibitor) per mol at the active site and also binds acarbose nonspecifically [24].

Other interactions of AMY2B

• Crude porcine pancreatic alpha-amylase was purified using a glycogen precipitation method [25].
• In a series of 10 healthy pigs, the normal ranges of the following biochemical parameters in blood serum were assessed: creatinine, urea, mineralogram (Na, K, Cl), uric acid, bilirubin, total protein, cholesterol, blood lipid level, thymol turbidity reaction and activities of alkaline phosphatase, alpha-amylase and transaminases [26].
• The HAin was inactivated by 2-ME and was gradually inactivated by pepsin, formalin and DTT, but not by beta-glucosidase, trypsin, alpha-amylase, papain, phospholipase C, neuraminidase, KIO4, and ethylendiamine tetraacetic acid (EDTA) treatments [27].

Analytical, diagnostic and therapeutic context of AMY2B

• Molecular cloning and primary structure analysis of porcine pancreatic alpha-amylase [28].
• A full-length alpha-amylase cDNA was obtained using a combination of library screening and nested polymerase chain reaction [28].
• Direct binding of three types of N-glycans to the alpha-amylase was demonstrated by surface plasmon resonance [9].
• Its interaction with porcine pancreatic alpha-amylase was characterized by inhibition kinetics, fluorescence competition assays with natural alpha-amylase inhibitors, and isothermal titration calorimetry [16].
• Minces of porcine pancreas maintained a linear rate or protein synthesis for more than 4 h with similar kinetics in the presence of absence of hormones. alpha-Amylase protein, quantitated by using glycogen percipitation, SDS polyacrylamide gel analysis, and radioimmunoassay, was found to represent 6-7% of the total protein content of the minces [29].

References