Studies on carbohydrate moieties of the glycoprotein, glucoamylase II of Aspergillus niger: nature of carbohydrate-peptide linkage and structure of oligosaccharides

Electrophoretically homogeneous type 1 (GP-C1 and GP-C2), type 2 (GP-C3a and GP-C3b,) and type 3 (GP-D1, and GP-D2) glycopeptides from Aspergillus niger glucoamylase II (Manjunath and Raghavendra Rao, preceding paper) were separately treated with alkaline borohydride. The (β-eliminated oligosaccharides were subjected to single and sequential digestion with specific glycosidases and the products analysed by gas liquid chromatography. The studies revealed that carbohydrate moieties were present as mannose, Man-Man-, and trisaccharide structures, namely, (a) GIc-Man-Man-, (b) Gal-Man-Man, (c) Man-Man-Man-, (d) GlcNAc-Man-Man-, and (e) Xyl-Man-Man. None of the glycopeptides contained all the trisaccharide structures (a) to (e). Type 1 glycopeptide contained structures (a), (b) and (c); type 2, (a) and (d) and type 3, (a), (b) and (e). The number of carbohydrate units (mono-, di-and trisaccharides) present in the major glycopeptides was determined and tentative structures for the glycopeptides proposed. Carbohydrate units appeared to occur in clusters of 4 to 7 in each glycopeptide, a structure unique to the carbohydrate moiety in Aspergillus niger glucoamylase. Based on carbohydrate analysis and yields of glycopeptide, the number of units of each type of glycopeptide present in glucoamylase II was tentatively calculated to give two of type Man:Glc:Gal = 12-15:l:l, one of type Man:Glc:GlcN = 10-l1:1:2 and one of type Man :GIc :Gal:Xyl = 4-8:0.1:0.5-0.8:0.3-1 glycopeptides

Excretion of lysine by Micrococcus glutamicus

Analysis of intracellular and extracellular lysine concentration during lysine fermentation by Micrococcus glutamicus AEC RN-13-6/1 indicated that lysine excretion occurs against a concentration gradient towards the end of the fermentation period. The capacity to excrete lysine against a concentration gradient may be a factor contributing to the high yield of lysine

Comparative studies on glucoamylases from three fungal sources

Five commercial preparations of glucoamylases (three from Aspergillus niger, one each from Aspergillus foetidus and Aspergillus candidus) were purified by ultrafiltration, Sepharose-gel filtration and DEAE-sephadex chromatography. Two forms of the enzyme, namely glucoamylase I and glucoamylase II were obtained from the fungi except from one strain of A. Niger. All the enzymes appeared homogeneous by electrophoresis and ultracentrifugation. The specific activities varied between 85 and 142 units. The pH and temperature optima were between 4 and 5, and 60°C respectively. The molecular weight as determined by the sodium dodecyl sulphate-polyacrylamide gel electrophoresis ranged from 75,000 to 79,000 for glucoamylase I and 60,000 to 72,000 for glucoamylase II. Only A. niger glucoamylases contained phenylalanine at the N-terminal end. The amino acid composition of the enzymes was generally similar. However, A. niger and A. foetidus glucoamylases, in contrast to A. candidus enzymes, contained greater percentage of acidic than of basic amino acids. The enzymes contained 15 to 30% carbohydrate and 49 to 57 residues of monosaccharides per mol. A. niger enzymes contained mannose, glucose, galactose, xylose and glucosamine but the A. candidus enzyme lacked xylose and glucose and only xylose was absent in A, foetidus enzymes. Majority of the carbohydrate moieties were O-glycosidically linked through mannose to the hydroxyl groups of seline and threonine of the polypeptide chain

Studies on carbohydrate moieties of Aspergillus niger glucoamylase. II: Isolation, purification and characterization of glycopeptides

Six glycopeptide fractions namely GP-C1, GP-C2, GP-C3a, GP-C3b, GP-D, and GP-D2 were isolated after exhaustive digestion of glucoamylase II (Glucozyme) from Aspergillus niger with pronase. They were purified using gel-filtration. high-voltage paper electrophoresis and ion-exchange chromatography on Dowex-50 and Dowex-1. They appeared homogeneous on electrophoresis under different conditions of pHs. The molecular weights ranged from 1600 and 4000 for these glycopeptides. Ally of them contained serine at the N-terminal end. Serine and threonine were the major amino acids with glycine, alanine, proline and tryosine present as minor constituents. Carbohydrate analysis revealed the presence of different sugars. Based on this, the glycopeptides were grouped into three types: (1) GP-C1 and GP-C2 containing mannose, glucose and galactose; (2) GP-C3a, and GP-C3b,containing mannose glucose and glucosamine; and (3) GP-D1 and GP-D2, containing mannose. glucose, galactose and xylose. Most sugar constituents in each glycopeptide occured in non-integral ratios implying a microheterogeneity of the carbohydrate moiety in Aspergillus niger glucoamylase II

Keyword Specific Cloud Computing

It is now a known fact that Internet of things (Iot) and Cloud computing will be the way ahead. Store and transmit of massive amounts of data is on the cards in the coming years which will profoundly affect other areas of everyday life in the next generation. Cloud and Iot are merged together is seen as an enabler of a large number of application scenarios. As an example at the start of 2016 automakers are building a driverless taxi service. Keeping this in mind a novel idea of keyword based Cloud Computing is brought about in this paper which gives out entire data to the user if the user types the keyword of the required entity

Spectrophotometric assay of immobilized tannase

A procedure for the assay of immobilized tannase with Polyacrylamide gel, collagen and Duolite-S-762 as matrices is described. It is based on the spectrophotometric determination of gallic acid formed by the enzymatic hydrolysis of tannic acid. The kinetic parameters of the enzymatic reaction have been studied and an assay procedure has been formulated. This method appears to be much more accurate than those reported earlier

Identification of polymorphic microsatellite loci in the queenless, ponerine ant Diacamma ceylonense

Diacamma ceylonenseis a queenless, ponerine ant whose colonies are headed by a single, mated, egg-laying worker referred to as the gamergate. Thus, new colonies are a result of dispersal by wingless gamergates. This is expected to influence patterns of colony dispersal and spatial distribution of genetic variablity. In order to facilitate the study of population genetic structure we have identified six unique, polymorphic, microsatellite loci. We have used fluorescence tagged primers to detect polymorphism at these loci

Realization of Programmable BPSK Demodulator-Bit Synchronizer using Multirate Processing

This paper presents the design and implementation of programmable BPSK demodulator and bit synchronizer. The demodulator is based on the Costas loop design whereas the bit synchronizer is based on Gardner timing error detector. The advantage of this design is that it offers programmability using multi-rate processing and does not rely on computation of filter coefficients, NCO angle input for each specific data rate and thus avoids computational complexities. The algorithm and its application were verified on Matlab-Simulink and was implemented on ALTERA platform. A 32 kHz BPSK demodulator–bit synchronizer pair catering for data rates from 1 kbps to 8 kbps was implemented.DOI:http://dx.doi.org/10.11591/ijece.v4i3.556

Aspartokinase of a lysine producing mutant of Micrococcus glutamicus

Aspartokinase from Micrococcus glutamicus AEC RN-13-6/1 [a homoserine requiring, S-(2-aminoethyl)-L-cysteine resistant, lysine producing strain] was purified 71 fold. The partially purified enzyme was inhibited by L-lysine. L-threonine, L-methionine, L-isoleucine, L-valine and L-phenylalanine activated the enzyme and reversed the inhibition by L-lysine. Aspartokinase activity was not derepressed by growth-limiting concentrations of L-threonine and/or L-methionine. It was not repressed by an excess of L-lysine (20 mM) and/or L-isoleucine (15.3 mM). The degree of activation or inhibition by amino acids was dependant on the composition of the growth medium. This observation is in contrast with the enzyme from the original (non-lysine-producing) strain which was inhibited by lysine or threonine and in a concerted manner by threonine plus lysine