Showing papers on "Melibiose published in 1972"

Induction and Characterization of β-Galactosidase in an Extreme Thermophile

Abstract: A thermostable beta-galactosidase (EC 3.2.1.23; beta-dgalactoside galactohydrolase) was found to be inducible in an extreme thermophile resembling Thermus aquaticus. Enzyme induction was achieved by the addition of lactose, galactose, or the alpha-galactoside, melibiose, to growing cultures. The addition of glucose to induced cultures had a repressive effect on further enzyme synthesis. The enzyme was purified 78-fold, and the optimum temperature and pH for activity were determined to be 80 C and pH 5.0, respectively. The enzyme was activated by both manganese and ferrous iron. Sulfhydryl activation and thermal stabilization indicate that the thermophilic beta-galactosidase is a sulfhydryl enzyme. Kinetic determinations at 80 C established a K(m) of 2.0 x 10(-3)m for the chromogenic substrate o-nitrophenyl beta-d-galactopyranoside (ONPG) and a K(1) of 7.5 x 10(-3)m for lactose. The Arrhenius energy of activation (for the hydrolysis of ONPG) was calculated to be 13.7 kcal/mole. A molecular weight of 5.7 x 10(5) daltons was estimated by elution of the enzyme from Sephadex 4B.

The sugars of some florida nectars

Abstract: A B S T R A C T The quantitative composition of major sugars in the nectars of 35 plant species was compared with that of 12 fruit juices. The use of specific quantitative assays for glucose, fructose, and sucrose made it possible to analyze large samples without quantitative chromatographic separations. Sucrose ranged from 0-99%. In most nectars, glucose and fructose were present in approximately equal amounts. No evidence was found for the presence of maltose, raffinose, and other oligosaccharides. LITTLE INFORMATION is available on the sugar composition of nectars. This may be due to the small size of the samples usually available and the lack of specific microanalytical techniques. Wykes (1952) used paper chromatography to separate the main sugars from nectars. Fructose and glucose were eluted from the paper and quantitated by reduction of copper. Maltose was claimed to be present in a few samples. The nonreducing sucrose was not determined. Furgala, Gochnauer, and Holdaway (1958) used a similar method to separate the sugars of some northern clover nectars but assayed the eluates with a phenol sulfuric acid reagent, which reacts also with sucrose. Their results suggest that maltose comprises 3-10 % of the total sugars present. Percival (1961) separated a large number of nectars by paper chromatography and estimated the preponderance of glucose, fructose, and sucrose after spraying with anisidine. Small amounts of material with RF values corresponding with maltose, melibiose, or raffinose were found in several species, but these oligosaccharides were not further

Genes for the fermentation of maltose and -methylglucoside in Saccharomyces carlsbergensis.

Abstract: 1. Saccharomyces carlsbergensis N.C.Y.C.74 was shown to be diploid and heterothallic. On acetate medium four spored asci were produced with a spore viability of no more than 2%. However diploid hybrids from the viable spores yielded asci with a spore viability of 75%, thus making tetrad analysis and consequently a genetical study of sugar fermentation in this strain feasible. 2. Auxotrophic mutants in a haploid derivative of this strain were obtained, some of which could be classified as ade1, ade2, ade4, ade5, ade6, ade7, ura2, ura3, lys1, trp2, trp5, his4 and his5. 3. 150 Random spores all fermented glucose, sucrose, mannose, galactose, melibiose, raffinose, and maltose, but only 28% fermented α-methylglucoside. The same fermentation pattern was found in petites of these 150 spores, except that 40% grew poorly on galactose; this gal phenotype could not be ascribed to a single gene. 4. In crosses with mal strains the maltose fermenting ability of the spores from S. carlsbergensis appeared to be dependent upon 1 single gene, which could be identified as MAL6, one of the 7 known polymeric genes for maltose fermentation in Saccharomyces. 5. Our strain was found to be heterozygous for 2 unlinked MGL genes, in this paper indicated as MGLa, and MGLb, both indispensable for the fermentation of α-methylglucoside. 6. After mutagenesis of a haploid strain with genotype MGLaMGLb, one mgl mutant was found, which complemented a strain with genotype mglamglb. This third indispensable MGL gene, preliminarily called MGLc, is homozygously present in our strain and is not linked to either MGLa or MGLb.

A bacterial phosphotransferase system and its role in sugar transport

Abstract: A bacterial phosphotransferase system catalyzes the transfer of phosphate from phosphoenolpyruvate to a number of sugars This system has recently been shown to be involved in a variety of important physiological processes in the bacterial cell, the best defined function being in the transport of various carbohydrates across the cell membrane by the process of group translocation Less well defined functions of the system are in the regulation of inducible enzyme synthesis, the regulation of intracellular levels of cyclic AMP, motility, etc Permeases which transport sugars not phosphorylated by the phosphotransferase system also appear to be regulated by this system Studies with one such sugar, melibiose, indicate that this sugar is co-transported with sodium ion and the kinetics of the melibiose permease in Gram-negative organisms indicates that it functions in the same manner as the amino acid and sugar transport systems of animal cells

Blood Group Substance-degrading Enzymes Obtained from Streptomyces sp.: Part II. Purification and Characteristics of α-Galactosidase from Streptomyces 9917S2

Abstract: The blood group B substance-degrading activity of Streptomyces 9917S2 is induced by galactosides as α-galactosidase activity is. Purification of the α-galactosidase was attempted by chromatography on DEAE-Sephadex and Sephadex. The purified preparation was shown to be free from α- and β-glucosidases, β-galactosidase, α- and β-glucosaminidases, and α- and β-galactosaminidases activities. The blood group B substance-degrading activity was present only in this fraction. This enzyme preparation cleaves α-(1→3)- and α-(1→6)-galactosidic linkages. The activity is inhibited by d-galactose, melibiose, and raffinose and also by l-arabinose and d-xylose.

Enzymatic quantitative determination of hexoses, singly and in mixtures with their oligosaccharides

Abstract: New Phytol. (1972) 71, 307-315. ENZYMATIC QUANTITATIVE DETERMINATION OF HEXOSES, SINGLY AND IN MIXTURES WITH THEIR OLIGOSACCHARIDES BY ROBERT ERNST AND JOSEPH ARDITTI Department of Developmental and Cell Biology, University of California, Irvine, California, 92664, U.S .A. (Received 16 August 1971) SUMMARY Quantitative determinations of a number of naturally ocurring D-hexoses and their oligo- saccharides can be accomplished by combinations of enzymatic methods without prior separa- tion of the sugars. T hese spectrophotometric methods employ readily-available enzymes and o maltose or lactose mixed with galactose and/or glucose; melibiose in mixtures with raffinose, and other combinations. INTRODUCTION Many chemical and enzymatic methods have been described for qualitative and quanti- tative determination of naturally-occurring sugars (Aminoff et al., 1970; HoUigan, 1971; Holligan and Drew, 1971; Lewis and Smith, 1967). The latest employ gas-liquid chroma- tography (GL C). Since GLC is not yet widely available 'to botanists, this paper presents modified enzymatic methods for the rapid quantitative determination of mixtures of oligosaccharides and their component monosaccharides. These methods, which employ readily-available enzymes and commerical reagents, have been used in studies of carbohydrate physiology of orchid seedlings (Ernst, 1967; Ernst, Arditti and Healey, 1972). MATERIALS AND METHODS Sugars. Melibiose and stachyose were obtained from Calbiochem, Los Angeles, California and other sugars from Pfanstiehl Laboratories, Inc., Waukegan, Illinois. Only D-sugars were employed. They were dissolved either in distilled water and kept frozen until used or in methanol-water (7 : 3, v/v) and stored at room temperature. Enzymes. Fructofuranosidase (invertase) melibiase free, u6 U/mg, derived from bakers' yeast, Grade IV was obtained from Sigma Chemical Company, St Louis, Mo. An alternative grade, purchased from Calbiochem Wallerstein invertase activity 873 (Meister, 1965), gave comparable results. Yeast a-glucosidase (maltase) suspension, 2 mg protein/ml (20 U/ml) and galactose dehydrogenase (Galactose UV-test, TC-GA 15921 TGAN) were obtained from Boeh- ringer Mannheim Corporation (BMC), San Francisco, California. P-Galactosidase (lactase), derived from Escherichia coli, 5.5 mg protein/ml (398 U/mg)

Blood Group Substance-degrading Enzymes Obtained from Streptomyces sp. Part II

Abstract: The blood group B substance-degrading activity of Streptomyces 9917S2 is induced by galactosides as α-galaetosidase activity is. Purification of the α-galactosidase was attempted by chromatography on DEAE-Sephadex and Sephadex. The purified preparation was shown to be free from α- and β-glucosiclases, β-galactosidase, α- and β-glucosaminidases, and α-and β-galactosaminidases activities. The blood group B substance-degrading activity was present only in this fraction. This enzyme preparation cleaves α-(1→3)- and α-(1→6)-galactosidic linkages. The activity is inhibited by D-galactose, melibiose, and raffinose and also by L-arabinose and D-xylose.

Method for manufacture of alpha-galactosidase by microorganisms

Abstract: MYCELIA HAVING STRONG A-GALACTOSIDASE ACTIVITY AND VERY WEAK INVERTASE ACTIVITY ARE OBTAINED BY CULTURING A MOLD BELONGING TO THE GENUS ABSIDIA IN A CULTURE MEDIUM INCORPORATING THEREIN AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF LACTOSE, MELIBIOSE, RAFFINOSE AND GALACTOSE. WHEN BEET MOLASSES IS TREATED WITH THE SAID MYCELIA, RAFFINOSE CONTAINED IN THE MOLASSES IS DECOMPOSED INTO SUCROSE AND GALACTOSE. THUS, THE YIELD OF SUCROSE CAN BE INCREASED.