Melibiose

About: Melibiose is a research topic. Over the lifetime, 1002 publications have been published within this topic receiving 27300 citations. The topic is also known as: Melibiose.

Purification and characterization of two lectins from the sea cucumber Stichopus japonicus

Abstract: Two Ca(2+)-dependent lectins were purified from the sea cucumber Stichopus japonicus by affinity chromatography on lactosyl-Sepharose 4B and ion-exchange chromatography on Q-Sepharose. Their molecular masses were estimated to be 13kDa (SJL-I) and 15 kDa (SJL-II) on SDS-PAGE. SJL-I agglutinated rabbit erythrocytes as well as human A, B, and O-type erythrocytes, but SJL-II agglutinated only rabbit erythrocytes. Hemagglutination by SJL-I was competitively inhibited by N-acetyl-D-galactosamine and galactose-containing carbohydrates. On the other hand, only lactose, melibiose, and raffinose gave weak inhibition of hemagglutination by SJL-II, suggesting that SJL-II may have high specificity for particular complex carbohydrate(s) on the surface of rabbit erythrocytes. SJL-II was activated at ten times lower Ca2+ concentration than SJL-I. Both lectins lost activity in acidic pH, while SJL-I appeared more stable down to pH 4.5.

Production and partial characterization of -galactosidase activity from an Antarctic bacterial isolate, Bacillus sp. LX-1

Abstract: An Antarctic Bacillus sp. isolate was found to exhibit extracellular α-galactosidase activity. On the basis of the results of 16S rRNA sequencing, the strain was named Bacillus sp. LX-1. In a one-factor-at-a-time experiment, galactose, peptone and Mn 2+ were found to be the medium components that facilitated enzyme production. The new strain showed optimal α-galactosidase activity at pH 7.0 and temperature of 40°C. The enzyme exclusively hydrolyzed α-D-galactosides such as p-nitrophenyl--galactopyranoside, melibiose, raffinose and stachyose, and showed no effect with proteases such as trypsin, pancreatin, and pronase. Enzyme activity was almost completely inhibited by the presence of Ag + , Hg 2+ , Cu 2+ , and sodium dodecylsulfate (SDS) but was unaffected by β-mercaptoethanol and ethylenediaminetetraacetic acid (EDTA). The LX-1 α-galactosidase may be a promising candidate as a biocatalyst for soybean processing in food and feed industries. Key words: Antarctic, Bacillus sp., α-galactosidase, one-factor-at-a-time, biocatalyst.

Methods for the study of the melibiose carrier of Escherichia coli.

Abstract: Publisher Summary This chapter describes methods used for measuring the transport of both the sugar and cation substrates. Some of these methods such as the preparation of radioactive melibiose and the construction of the Li+-selective electrode were devised specifically for studies of the melibiose transport system. The melibiose carrier of Escherichia coli is a representative of the class of carriers that require a cation for cotransport. An unusual feature of this transport system is that it is able to utilize Na + , Li + , or H + as the coupling cation depending on the conditions. Another interesting property of the carrier is that different sugar substrates show different specificities for the cation requirement. A variety of strains of E. coli has been isolated for use in experiments on the melibiose carrier. It is essential to start with a strain from which the lactose carrier (lac Y) has been deleted, as the lac carrier also is capable of transporting melibiose. The growth of normal E. coli cells on melibiose minimal medium is strongly inhibited by 10 mM Li + and it is therefore possible to isolate Li + -resistant mutants. This organism is dependent on Na + or Li + for growth on melibiose as it has lost the ability to transport the disaccharide with protons.

Human serum antibodies to melibiose and other carbohydrates.

Abstract: Human sera were screened by passive haemagglutination for antibodies to various sugars. A high incidence of antibodies to melibiose was observed. There were also a few antibodies to other sugars and to dextran.