Topic
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.
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TL;DR: The invertases were different between all of the serotype but similar within the serotypes, and these findings support the taxonomic schemes of Coykendall and of Bratthall.
Abstract: Sucrase activity was studied in 13 strains of Streptococcus mutans representing the five Bratthall serotypes. Sucrose-adapted cells have sucrase activity in the 37,000 x g-soluble fraction of all strains. The enzyme was identified as invertase (beta-d-fructofuranoside fructohydrolase; EC 3.2.1.26) because it hydrolyzed the beta-fructofuranoside trisaccharide raffinose, giving fructose and melibiose as its products, and because it hydrolyzed the beta-fructofuranoside dissacharide sucrose, giving equimolar glucose and fructose as its products. Invertases of c and e strains exhibit two activity peaks by molecular exclusion chromatography with molecular weights of 45,000 to 50,000 and about 180,000; those of serotypes a, b, and d strains exhibit only a single component of 45,000 to 50,000 molecular weight. The electrophoretic mobility of invertases is different between the serotypes and the same within them. Inorganic orthophosphate (P(i)) has a weak positive effect on the V(max) of invertases of serotypes c and e cells but a strong positive effect on the invertases of serotype b cells; P(i) has a strong positive effect on the apparent K(m) of the invertases of serotype d cells, but has no effect on the V(max); P(i) has a strong positive effect on both the apparent K(m) and V(max) of the invertases of serotype a cells. Thus, the invertases were different between all of the serotypes but similar within the serotypes. These findings support the taxonomic schemes of Coykendall and of Bratthall. It was additionally noted that 37,000 x g-soluble fractions of only serotypes b and c but not serotypes a, d, and e cells have melibiase activity, and it could be deduced that serotype d cells lack an intact raffinose permease system.
31 citations
TL;DR: In this paper, the authors examined the initiation and growth of cucumber hypocotyl callus on galactose, glucose, sucrose, melibiose, raffinose, stachyose, and sucrose + Galactose (1 : 1, w/w) carbon sources.
31 citations
TL;DR: Comparing the wild-type and mutant strains concerning their steady state pH gradient and their rates of H+ influx following oxygen pulses suggests that mutations at position 302 cause a sugar-dependent H+ leak.
31 citations
TL;DR: The survival of larvae which had fed on sugar-treated Styropor for 3 days was the longest on sucrose, maltose, glucose, fructose, raffinose and melezitose, and no antagonistic or inhibitory effects were found.
31 citations
TL;DR: A Monascus pilosus strain was selected for production of intracellular α-galactosidase and the enzyme was purified by ammonium sulfate precipitation, gel filtration, and ion exchange chromatography and was demonstrated to be homogeneous by slab gel electrophoresis.
Abstract: A Monascus pilosus strain was selected for production of intracellular α-galactosidase. Optimum conditions for mycelial growth and enzyme induction were determined. Galactose was one of the best enzyme inducers. The enzyme was purified by ammonium sulfate precipitation, gel filtration, and ion exchange chromatography and was demonstrated to be homogeneous by slab gel electrophoresis. The molecular weight of this enzyme, estimated by gel filtration, was about 150,000. The optimum conditions for the enzyme reaction was pH 4.5 to 5.0 at 55°C. The purified enzyme was stable at 55°C or below and in buffer at pH 3 to 8. The activity was inhibited by mercury, silver, and copper ions. The kinetics of this enzyme, with p-nitrophenyl-α-d-galactoside as substrate, was determined: Km was about 0.8 mM, and Vmax was 39 μmol/min per mg of protein. Enzymatic hydrolysis of melibiose, raffinose, and stachyose was analyzed by thin-layer chromatography.
31 citations