Combinations of Various Metals with Urease of Amoebocytes of Limulus or with its Coenzyme.

Abstract

In former papers Loeb and Bodansky 1 have shown that if amoebocyte tissue of Limulus is extracted with various salts, the activity of urease in the extract differs very much in accordance with the character of the metal present in the salt. Furthermore, Loeb, Lorberblatt and Field 2 found that after extraction with NaCl a subsequent addition of CaCl₂ is without benefit, while after extraction with MgCl₂ subsequent addition of CaCl₂ increases markedly the efficiency of the extract.

In continuing these investigations we found that after extraction with certain salts in which the character of the anion is the same but which differ in respect to the kation, the efficiency coefficients of the various urease preparations differ very much from each other; we found that by adding a second salt to the extract made with a first salt the urease preparation can, under certain conditions, be made to assume the efficiency coefficient characteristic of the second salt and the readiness with which this transformation can be accomplished may be represented in definite curves, the abscissa of which indicates the time at which the second salt was added and the ordinate the amount of urease transformed into the new urease preparation. These curves are specific for each combination used. Thus, if we add NaCl to CaCl₂ extract one hour after the beginning of the extraction, almost one-half the CaCl₂ effect can be replaced by the NaCl effect; but during the next 4 hours the CaCl₂ effect gradually increases in strength and at last has become so strong that it remains unaffected by addition of NaCl. In the urease preparation obtained by extraction with NaCl, only within the first 30 minutes after the beginning of extraction can the CaCl₂, effect replace to a slight extent the NaCl effect. After completion of extraction (2 hours) the effect of addition of Ca has become nil. Thus each preparation has a specific time curve.