The labelling of human serum by 32P-DiIsopropylphosphorofluoridate (DF32P)

1. 1. On paper electrophoresis the pseudo-cholinesterase activity of human serum is localised between the α-2 and the β-peak. 2. 2. The same localisation is found after electrophoresis on starch columns. 3. 3. Thoroughly dialysed DF32P treated human sera as well as sera obtained from humans a few days after the injection of DF32P were submitted to zone electrophoresis. No radioactivity could be detected on the paper electrophoresis strips, but after column electrophoresis it was possible to localise the radioactivity between the α-2 and the β-peaks. 4. 4. The conclusion is reached that in human sera, which have been in contact with DF32P, only one component, the pseudo-cholinesterase, is irreversibly labelled by 32P. The values obtained for the turnover of serum proteins by means of DF32P therefore clearly reflect the turnover of the pseudo-cholinesterase component. © 1957

არჩილ ციციშვილი და მამა-შვილი კერესელიძეები

არჩილ ციციშვილი ლულუ კერესელიძესა და მის ვაჟთან, გიორგისთან ერთად. ფოტოს გადაღების ადგილი და თარიღი უცნობია

Purification and properties of dialkylfluorophosphatase

1. 1. Zone electrophoresis on starch columns of purified preparations of fluorophosphatase resulted in a further purification. The preparations thus obtained differed in various respects from the cruder ones so far described. 2. 2. In the course of this electrophoresis fractions were obtained, which, although themselves almost or entirely lacking enzymic activity, could activate the enzyme. This activation was particularly impressive when studied in the presence of Mn++ ions. The activation is very marked when DFP is used as a substrate. In the case of other substrates, the activation usually also occurs although it is less marked. 3. 3. Mn++ ions activate the hydrolysis of DFP and tabun but inhibit that of most other substrates. 4. 4. p-Chloromercuribenzoic acid inhibits the enzyme. This inhibition is wholly or partially reversible by cysteïne. 5. 5. The hydrolysis was studied with a number of substrates. It is probably due to one and the same enzyme, present in the purified preparations, although the possibility that the hydrolysis of tabun requires a second enzyme could not be excluded. 6. 6. Intravenous injection of DFPase preparations afforded a certain amount of protection in rats when given previous to lethal dosages of DFP or sarin. © 1957