Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Specific growth rates, growth yields, and the level and cellular distribution of three sucrose-metabolizing enzyme activities were determined for seven oral streptococci (Streptococcus mutans strains E49, BHT, 10449, SL-1, and LM-7, S. sanguis 10558, and S. salivarius 25975). Cultures were grown in a fermentor at pH 6 with either 20 mM glucose or 10 mM sucrose. Generation times varied between 21 and 70 min. Whereas some strains grew 10 to 50% more slowly with sucrose than with glucose, others did not. Growth was always logarithmic, and the growth yields were similar. Glcosyl transferase (EC 2.4.1.5) was largely extracellular; in sucrose cultures it was appreciably lower, but no major shift to a cell-associated form was found. In glucose cultures, the activity varied between 4 and 140 IU per 6-liter culture. The glucan formed was mostly or exclusively water insoluble. Glcosyl transferase was stimulated weakly (60% or less) by various dextrans. Fructosyl transferase (EC 2.4.1.10) was primarily extracellular (except in glucose cultures of S. salivarius) and varied between 0 and 337 IU/culture. In S. salivarius, the extracellular fructosyl transferase was induced by sucrose. In all S. Mutans cultures, the total fructosyl transferase activity was lower after growth with sucrose. All strains had extra- and intracellular invertase (EC 3.2.1.26) activity. Total levels varied between 210 and 3,500 IU/culture. Less extracellular activity was present in sucrose cultures. Only S. salivarius had appreciable activity in the cellular particulate fraction. Invertase activity was significantly higher than the combined glucosyl and fructosyl transferase activities in all cultures.
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PMID:Occurrence and distribution of sucrose-metabolizing enzymes in oral streptococci. 97 54

Intervase from extracellular culture fluids of S. mutans strain SL-1 was shown to have the same characteristics as intracellular invertase from the same strain. The data indicate that intracellular invertase is released into the culture fluids primarily during the late log and stationary phases of growth.
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PMID:Invertase in cell-free culture fluids of Streptococcus mutans strain SL-1. 121 52

Sucrose dissimilation was studied in five strains of Streptococcus mutans. Glucose-adapted strain SL-1 makes acid more slowly from sucrose than from glucose; glucose-adapted strain SL-1 gives diauxie growth kinetics in broth containing limiting amounts of both glucose and sucrose. Thus, at least part of the sucrose dissimilative system appears inducible. Sucrase activity was identified in the 37,000 x g soluble cell fraction of five strains. Its intracellular location implies the presence of sucrose permease. The specific activity of the sucrase is higher in sucrose-adapted cells than in cells adapted to glucose or other sugars, further suggesting its inducibility. The enzyme from strain SL-1 was partially purified by diethylaminoethyl-cellulose chromatography and shown to be a single molecule with a molecular weight of about 48,000. The partially purified enzyme is specific for sucrose and produces equimolar glucose and fructose. Since it degrades raffinose, but not melezitose or other alpha-glucosides, it is an invertase. The invertase has a relatively high K(m) for its substrate and a pH optimum of 5.5 to 6.2. It is activated by inorganic orthophosphate (P(i)), P(i) functioning as a positive effector. Arsenate can substitute for phosphate. Neither the crude cell-free extract nor the partially purified enzyme preparations has detectable sucrose phosphorylase activity. A possible potent role of the invertase in the regulation of sucrose carbon flow in S. mutans is discussed.
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PMID:Identification, preliminary characterization, and evidence for regulation of invertase in Streptococcus mutans. 474 13