Purification and characterization of a lytic peptidase produced by Bdellovibrio bacteriovorus 6-5-S

1973 ◽  
Vol 19 (5) ◽  
pp. 659-666 ◽  
Author(s):  
H. B. Fackrell ◽  
J. Robinson

Bdellovibrio bacteriovorus 6-5-S releases at least two enzymes into the culture fluid when grown on autoclaved cells of Spirillum serpens VHL. One of the enzymes is bacteriolytic and the other is proteolytic. The lytic enzyme was purified by a factor of 3000 using ammonium sulfate fractionation, Sephadex G-100 gel filtration, and the anion exchanger DEAE-Sephadex. The lytic enzyme degrades peptidoglycan of S. serpens by hydrolyzing the diaminopimelic acid – alanine bond in the tetrapeptide chain. Ca2+ or Mg2+ exerted little or no effect on the activity of the lytic enzyme. The enzyme had a molecular weight of 40 000 as indicated by gel filtration. Crude preparations were unstable at 4C. The second enzyme, a protease that digested Azocoll, was purified by a factor of 7 by ammonium sulfate fractionation followed by gel filtration with Sephadex G-100. The protease was eluted in the void volume from a Sephadex G-100 column and therefore may have a molecular weight of at least 100 000. Its activity was enhanced by additions of Ca2+ and Mg2+. The enzyme was stable at 4C.

1973 ◽  
Vol 19 (4) ◽  
pp. 427-438 ◽  
Author(s):  
J. W. Coulton ◽  
M. Kapoor

NADP-specific glutamate dehydrogenase (GDH) from Salmonella typhimurium was purified 190-fold by heat treatment, ammonium sulfate fractionation, DEAE-Sephadex chromatography, reverse ammonium sulfate fractionation, and gel filtration. The enzyme proved to be stable to 55 °C, and displayed a pH optimum at 8.6 in the amination reaction. The sedimentation coefficient of GDH, as determined by sucrose density gradient centrifugation, was about 10.3 S. From gel filtration chromatography, the molecular weight and Stokes' radius for the enzyme were estimated at 280 000 daltons and 54 × 10−8 cm, respectively. Unusual resistance was displayed by the enzyme to high concentrations of the protein denaturants, urea, SDS, and guanidine hydrochloride.


1970 ◽  
Vol 131 (5) ◽  
pp. 1004-1015 ◽  
Author(s):  
Adnan S. Dajani ◽  
Ernest D. Gray ◽  
Lewis W. Wannamaker

A bactericidal substance previously isolated from phage type 71 Slaphylococcus aureus has been further identified and characterized. Staphylococci belonging to phage type 71 produce the substance in higher titers than staphylococci lysed by other phages in group II in addition to phage 71. Other staphylococci do not produce the bactericidal substance. The bactericidal substance shares several of the properties of bacteriocins but differs from this group of antibiotic substances in some respects. A combination of ammonium sulfate fractionation and gel filtration on a Sephadex G-100 column resulted in considerable degree of purification of the bactericidal substance. The substance is a previously unrecognized product of S. aureus and is distinct from other extracellular products of this organism.


2011 ◽  
Vol 393-395 ◽  
pp. 890-893
Author(s):  
Jian Wei Cen ◽  
Shu Xian Hao ◽  
Lai Hao Li ◽  
Xian Qing Yang ◽  
Hui Huang ◽  
...  

Ammonium sulfate fractionation was implicated as one of essential steps to purified Myoglobin (Mb).We adopted SDS-PAGE analysis and absorption spectra scanning to demonstrate the effect of ammonium sulfate on Mb and its derivatives. The results shown that protein with the molecular weight above 37.8kDa were dominated in myoglobin extract of tilapia, which can be precipitated with ammonium sulfate. Mb molecular weight of tilapia is about 15.8 kDa, which can be collected by the treatment of ammonium sulfate with saturation between 60%-70% to remove unwanted protein. The absorption spectra show that Mb derivatives could be transferred to met-myoglobin after preliminary fractionating with ammonium sulfate.


1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.


1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.


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