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Nejvíce citované: 4980196

6 citací v PubMed Filtry

Nejvíce citovaný článek - PubMed ID 4980196

Záznam nenalezen v Medvik. Navštivte PubMed 4980196

Článek

Mutants of Bacillus megaterium with altered synthesis of an exocellular neutral proteinase

Folia microbiologica. 1984 ; 29 (2) : 99-103.

Folia Microbiol (Praha)
ISSN 0015-5632
Zdroj

Germinated spores of Bacillus megaterium were mutagenized with ethyl methanesulphonate and spread on test agar with caseinate. Colonies with altered proteolytic zones or morphology were isolated and tested in liquid media. The mutants can be divided into four groups: A) those producing more proteinase in both growth and sporulation media, B) those producing the same amount of the enzyme in growth medium but higher amount in sporulation medium, C) those producing less proteinase in the growth medium and more in the sporulation one, D) those producing less or no enzyme. Clones of the first three groups were phenotypically asporogenic. All mutants producing more enzyme during growth retained their sensitivity to repression by amino acids. Isolation of mutants of types B) and C) supports the idea of differences in the control of proteinase synthesis during growth and during sporulation.

MeSH
Bacillus megaterium enzymologie genetika růst a vývoj MeSH
endopeptidasy biosyntéza MeSH
kultivační média MeSH
mutace * MeSH
neprilysin MeSH
Publikační typ
časopisecké články MeSH
Názvy látek
endopeptidasy MeSH
kultivační média MeSH
neprilysin MeSH

Článek

Intracellular proteolytic activity during sporulation of Bacillus megaterium

Folia microbiologica. 1977 ; 22 (1) : 1-11.

Folia Microbiol (Praha)
ISSN 0015-5632
Zdroj

Intracellular proteolytic activity increased during incubation of the sporogenic strain of Bacillus megaterium KM in a sporulation medium together with excretion of an extracellular metalloprotease. The exocellular protease activity in a constant volume of the medium reached a 100-fold value with respect to the intracellular activity. Maximal values of the activity of both the extracellular and intracellular enzyme were reached after 3-5 h of incubation. After 7 h 20-50% cells formed refractile spores. The intracellular proteolytic system hydrolyzed denatured proteins in vitro at a rate up to 150 mug mg-1 h-1 and native proteins at a rate up to 70 mug mg-1 h-1. Degradation of proteins in vivo proceeded from the beginning of transfer to the sporulation medium at a constant rate of 40 mug mg-1 h-1 and the inactivation of beta-galactosidase at a rate of 70 mug mg-1 h-1. The intracellular proteolytic activity was inhibited to 65-88% by EDTA, to 23-76% by PMSF. Proteolysis of denatured proteins was inhibited both by EDTA and PMSF more pronouncedly than proteolysis of native proteins; 50-65% of the activity were localized in protoplasts. Another strain of Bacillus megaterium (J) characterized by a high (up to 90%) and synchronous sporulation activity was found to behave in a similar way, but the rate of protein turnover in this strain was almost twice as high. The asporogenic strain of Bacillus megaterium KM synthesized the exocellular protease in the sporulation medium, but its protein turnover was found to decrease substantially after 3-4 h. The intracellular proteolytic system of the sporogenic strain J and the asporogenic strain KM were also inhibited by EDTA and PMSF.

MeSH
Bacillus megaterium enzymologie růst a vývoj MeSH
bakteriální proteiny metabolismus MeSH
EDTA farmakologie MeSH
endopeptidasy metabolismus MeSH
fenylmethylsulfonylfluorid farmakologie MeSH
mutace MeSH
protoplasty enzymologie MeSH
spory bakteriální enzymologie růst a vývoj MeSH
Publikační typ
časopisecké články MeSH
Názvy látek
bakteriální proteiny MeSH
EDTA MeSH
endopeptidasy MeSH
fenylmethylsulfonylfluorid MeSH

Článek

Protease activity in cells of Bacillus megaterium during derepression

Folia microbiologica. 1975 ; 20 (4) : 277-88.

Folia Microbiol (Praha)
ISSN 0015-5632
Zdroj

A proteolytic activity hydrolyzing denatured proteins of Bacillus megaterium labelled with 35S or 14C amino acids was detected in cells of the asporogenic strain of Bacillus megaterium. The substrate is hydrolyzed by the enzyme or enzymes at optimum pH around 7, their activity being almost completely inhibited by EDTA and o-phenanthroline. PMSF, the inhibitor of serine proteases, is slightly inhibitory. Gel filtration on a Sephadex column separated the protease activity to two or three fractions. The protease activity in cells with the repressed synthesis of protease corresponds to 5-20 mug of substrate degraded per hour by 1 mg of protein at 37 degrees C. It increases five to ten-fold during the derepression. When the intracellular protease activity increases the extracellular enzyme begins to be excreted into the medium. The intracellular protease activity rapidly decreases after the addition of chloramphenicol or of a mixture of amino acids to the derepressed culture. Half or even more of the protease activity is released from the cells during their conversion to protoplasts by means of lysozyme. This "periplasmic" activity remains mostly in the supernatant also after mesosomes have been centrifuged down from the periplasm. A portion of the activity bound in protoplasts sediments together with membrane fraction after their lysis.