[Approaches to assessing dynamics of permeability and duration of thiaminase I action, administered parenterally to animals]. / Podkhody k otsenke dinamiki pronitsaemosti i prodolzhitel'nosti deistviia tiaminazy I, vvedennoi zhivotnym parenteral'no.

Two approaches and direct isotopic assay were employed to examine the time course of permeability and duration of action of tissue thiaminase I injected parenterally to albino mice. The injected enzyme was found to be detectable in renal and hepatic tissues 3 hours later. The action of the enzyme dermally injected in a dose of 1.2 IU/kg in the same tissues lasted 4 days. Experimental findings led to the conclusion that the thiamine degradation enzyme may be used in experimental biology in order to estimate the duration of its action and the time course of gross molecular permeability in the tissue of test animals.

[Direct measurement of the antivitamin action of parenterally injected thiaminase]. / Priamoe testirovanie antivitaminnogo deistviia tiaminazy, vvodimoi v organizm parenteral'no.

Thiaminase (EC 2.5.1.2) from freshwater bivalve molluscs is a polycosubstrate enzyme, which is resistant to temperatures below 55 degrees. The activation energy of the enzyme with cystein is 15077 cal/mole, with aniline--15948 cal/mole. Thiaminase when injected parenterally to albino mice 2 hrs after injection of [2-14C]thiamine causes an extensive destruction of labelled vitamin b1, which is evidenced from the [14C]thiazole content in urine, liver and kidneys. The total radioactivity and the content of [14C]thiazole in the urine samples collected within 6 hrs after thiamine injection are increased. Cysteine and histidine in combination with thiaminase have no activating effect similar to that observed "in vitro". In the experimental series when non-labelled vitamin B1 from animal tissues (liver, kidney, spleen, muscle) was substituted by the labelled one, the parenterally injected enzyme destroyed up to 30-50% of total thiamine content. Brain and skeletal muscle tissues are more resistant to thiaminase action.

[Antivitamin activity of thiaminase from B. thiaminolyticus with different routes of administration into animals]. / Antivitaminnaia aktivnost' tiaminazy iz B. thiaminolyticus pri razlichnykh sposobakh vvedeniia fermenta v organizm zhivotnogo.

Effect of bacterial thiaminase was studied in vivo after subcutaneous and intragastric administration of either the enzyme or of suspensions of intact and inactivated with an antibiotic bacterial cells, producing thiaminase. Activity of the thiamin-dependent enzymes (transketolase and alpha-ketoglutarate dehydrogenase) was distinctly decreased in liver and kidney tissues within 2 and 7 days after a single subcutaneous administration of 0.015 IU of the enzyme. Repeated administration of the enzyme within 4 days inhibited activity of thiamin-dependent enzymes in other tissues (heart, spleen, muscle and blood). Activity of thiamin-dependent enzymes in liver, kidney, heart, spleen, brain, muscles and blood was decreased more distinctly after administration of intact bacterial cells into mice stomach as compared to the effect of inactivated cells. Old animals were more sensitive to administration of intact bacterial cells than the young ones. The data obtained suggest that, besides the known thiamin-degrading effect of bacterial thiaminase in the intestinal contents, the enzyme exhibits functional activity within the animal tissues after the parenteral administration.