Beiträge zur Kenntnis der Argimase. IV. Mitteilung. Das Wasserstoffionenoptimum und die Reinigung der Arginase durch das Adsorptionsverfahren.

Edlbacher, S.; Simons, Elizabeth R.

doi:10.1515/bchm2.1927.167.1-3.76

Cited by 14 publications

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“…The experimental results upon which these several statements were based have been repeatedly confirmed in each of two laboratories, but they have not hitherto been published. It is the purpose of this paper to make good the omission.The relation of arginase activity to pH has been studied, it should be mentioned, not only by ourselves, but also by EDLBACHER and BONEM (4), HINO (5), and EDLBACHER and SIMONS (6). The work of EDLBACHER and BONEM, published in 1925 and therefore almost contemporaneous with our own, placed the optimum where we had found it-at pH 9 5 to 9-8.…”

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confidence: 65%

“…The relation of arginase activity to pH has been studied, it should be mentioned, not only by ourselves, but also by EDLBACHER and BONEM (4), HINO (5), and EDLBACHER and SIMONS (6). The work of EDLBACHER and BONEM, published in 1925 and therefore almost contemporaneous with our own, placed the optimum where we had found it-at pH 9 5 to 9-8.…”

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confidence: 65%

“…is at 9-8, but with respect to the quantity of substrate decomposed (under the conditions of that table) in 23 hours, it is to be set at an appreciably lower level. Here, possibly, is to be found the explanation of the rather low optimum indicated by such results as those of EDLBACHER and SIMONS (6). Here also, it may be said, lies the reason for the recommendation of HUNTER and DAUPHINEE (10), that in the quantitative determination of arginine, arginase should be used at a pH distinctly below the (initial) optimum.2…”

Section: Selected Experiments and Resultsmentioning

confidence: 93%

“…The other pairs of arginine and arginase tubes were treated seriatim, at convenient intervals, in an identical manner. Of the two samples thus submitted to incubation at any one pH, one was inactivated 6 hours, the other 24 hours, after the time of mixing. The inactivation and the subsequent determination of urea were carried out as in Experiment 1.…”

Section: Selected Experiments and Resultsmentioning

confidence: 99%

“…We have repeatedly confirmed the finding of GROSS (14), and of EDLBACHER and BURCHARD (15), that velocity coefficients calculated according to that law fall steadily with the progress of the reaction. As an incidental exemplification of this behaviour we have calculated, and included in Table V A reference to the tables mentioned, and especially to the rather extended series of observations recorded in the latter for pH 6 1 and pH 7.3, will show that at any pH below a certain limit (a limit lying evidently somewhere between 7-9 and 8.45) the equation yields values of k which remain constant, for a given set of conditions, until at least 50 per cent. of the initial substrate has been decomposed.'…”

Section: Selected Experiments and Resultsmentioning

confidence: 99%

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Arginase Studies.—i. The Relation Between the Activity of the Enzyme and the Concentration of Hydrogen Ions

Hunter

Morrell

1933

Exp Physiol

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June 1924 we reported that "the activity of arginase commences at pH 4X8, rises to a maximum at or near pH 9-8, and then falls so abruptly that at pH 11 X5 it is practically zero" (1). Incidental mention of the rather unusual position of the optimum was made in a paper published shortly afterwards by HUNTER and DAUPHINEE (2). Later, in 1927, we reported (3) to the American Society of Biological Chemists that the pH-activity curve of arginase, besides being as a whole strikingly unsymmetrical, took in its longer ascending limb the unusual form of two successive sigmoid curves of unequal size. The experimental results upon which these several statements were based have been repeatedly confirmed in each of two laboratories, but they have not hitherto been published. It is the purpose of this paper to make good the omission.The relation of arginase activity to pH has been studied, it should be mentioned, not only by ourselves, but also by EDLBACHER and BONEM (4), HINO (5), and EDLBACHER and SIMONS (6). The work of EDLBACHER and BONEM, published in 1925 and therefore almost contemporaneous with our own, placed the optimum where we had found it-at pH 9 5 to 9-8. The later experiments of EDLBACHER and SIMONS (1927) indicated the distinctly lower (and, we believe, less nearly correct) value of 9-0. HINO (1926) reported an optimum at 7-3 to 7-5. Oddly enough, a single experiment of our own (7), the first attempted, had given in 1922 a result not very different from that of HINO; but in no subsequent trial have we ever observed a maximal effect, for the early stages of the reaction, at any pH lower than 9-6.As a matter of fact, the true optimum is in all probability rather above 9*8 than below it. 1 Based upon a thesis presented by J. A. MORRELL in partial fulfilment of the requirements for the degree of Ph.D. at the University of Toronto.Hunter and Morrell MATERIALS AND GENERAL METHODS. (1) Arginase.-As a source of arginase we used a dry fat-free liver powder prepared from beef liver by the method of WIECRowSKI (8). As occasion arose, 10, or sometimes 15, grm. of such a powder were extracted for 24 hours with 100 c.c. of 50 per cent. glycerol. The extract was filtered through a bed of paper pulp, and the perfectly clear, light brown, slightly acid filtrate was titrated with N NaOH until its pH, electrometrically determined, was 7 0. Arginase solutions thus prepared and neutralised retained their activity unaltered for many weeks. In some experiments they were used directly, in others after dilution to an appropriate degree with water. They contained, of course, a considerable quantity of protein as well as other inactive material; but for our present purpose a high degree of purity in the enzyme was not considered to be essential. The several crude enzyme solutions from time to time employed varied considerably in activity; it is therefore seldom possible to compare one experiment with another upon the simple basis of the amount of liver extract in use.(2) Urease.-Active solutions of urease were obtained by extract...

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confidence: 65%

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confidence: 65%

Section: Selected Experiments and Resultsmentioning

confidence: 93%

Section: Selected Experiments and Resultsmentioning

confidence: 99%

Section: Selected Experiments and Resultsmentioning

confidence: 99%

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