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M Szymona

Publications and source records attributed to M Szymona.

At least 19 recordsLinked to original sources
PubMed1980

Occurrence of a large molecular size form of polyphosphate-glucose phosphotransferase in extracts of Mycobacterium tuberculosis H37Ra.

Extracts prepared by sonicating Mycobacterium tuberculosis H37Ra cells with subsequent centrifugation at 18,000 X g proved to contain a very large molecular size form of polyphosphate-glucose phosphotransferase. The enzyme was separable by polyacrylamide gel electrophoresis, DEAE-cellulose chromatography or ultracentrifugation. When rechromatographed at alkaline pH values, it gave rise to one of the soluble forms of lower molecular weight. The conversion also took place as a result of n-butanol extraction or salting out with ammonium sulfate and heating of dissolved pellet. Under certain conditions the lower-molecular weight enzyme converted to the higher-molecular weight form by association with a hitherto undefined cell constituent. It is assumed that both ionic and hydrophobic forces play a role in this interconversion phenomenon.

Cell Extracts↗
PubMed1977

Polyphosphate-glucose phosphotransferase. Purification of Mycobacterium tuberculosis H37Ra enzyme to apparent homogeneity.

1. The enzyme (EC 2.7.1.63) was isolated from glucose-grown M. tuberculosis H37Ra; during the purification procedure, 2-mercaptoethanol, glucose, EDTA and NaCl served as protecting agents. 2. The enzyme was purified about 600-fold. The preparation was homogeneous on polyacrylamide-gel electrophoresis and gave one precipitin line in double immunodiffusion test. Molecular weight of the enzyme determined by Sephadex G-100 filtration was about 118 000. 3. The enzyme preparation showed also glucokinase activity with ATP.

Cell-Free System↗
PubMed1976

Purification and properties of L-asparaginase from Mycobacterium phlei.

1. L-asparaginase from M. phlei was purified about 170-fold with an 11% yield. The purification procedure consisted of: fractionation with ammonium sulphate; adsorption of contaminating proteins on calcium phosphate gel; chromatography on Sephadex G-150 and DEAE-cellulose. The specific activity of the final preparation was 32.6 i.u./mg protein. 2. Molecular weight of the enzyme as determined by Sephadex G-100 filtration amounted to 126 000. Optimum pH was 8.8-9.2. The enzyme did not hydrolyse L-glutamine over the pH range 4-9, and was inhibited by D-asparagine. The apparent Michaelis constant for L-asparagine was 0.7 mM; energy of activation, 9800 cal/mole. 3. On polyacrylamide-gel electrophoresis the final preparation revealed two protein bands, one of which was coincident with the enzyme activity.

Asparaginase↗
PubMed1975

L-asparaginase activity of Mycobacterium phlei under various growth conditions.

Seven Mycobacterium strains were grown statically on salts-glycerol-asparagine (Sauton) or on salts-glucose-glutamate (Sym) media. At desired time of incubation, the bacteria were washed with water, disintegrated with powdered corundum and in resulting cell-free extracts L-asparaginase activity was determined by the Conway method. The majority of experiments were performed on M. phlei which exhibited considerable rise in L-asparaginase activity with increasing age of the culture. This change did not occur on Sym medium because of Zn2+, which proved to abolish the effect of the enzyme induction in vivo but did not inhibit the activity in vitro. Addition of rifampicin to Sauton culture media resulted in a low enzyme level. Exogenous asparagine and glycerol were not indispensable for the enzyme synthesis and could be replaced by glutamate and glucose, respectively.

Asparaginase↗