[Urocanic acid content of the epidermis of diabetics]. / Soderzhanie urokaninovoi kisloty v épidermise kozhi bol'nykh sakharnym diabetom.

A degree of a decrease in the content of urocanic acid in washes-off from the skin surface of patients with decompensated diabetes mellitus depends on a period and gravity of disease that may be indicative of disorders of the adenylate cyclase system (or one of its links). Change in the content of urocanic acid in the epidermis of patients with diabetes mellitus treated with the Biostator apparatus, correlates with change in the content of glucagon and blood sugar. The authors discuss a possibility to use the test of urocanic acid determination for the prediction and assessment of the efficacy of therapy of patients with diabetes mellitus.

[Biological activity of urocanic acid]. / Izuchenie biologicheskoi aktivnosti urokaninovoi kisloty.

Biological activity of urocanic acid was studied in a culture of CaOV cell in vitro and in mice with transferred tumors in vivo. Efficiency of urocanic acid in vitro was estimated by the rate of 3H-thymidine and 3H-uridine as well as 3H-lysine incorporation into cells, and in vivo by its influence on the tumor mass and on life duration of the tumor-bearing mice. Urocanic acid inhibited the protein synthesis in tumoral cells at the step of translation, retarding growth of various strains of transferring tumors in mice. The use of urocanic acid as an antitumoral drug is promising because the palliative effect obtained may be reinforced.

[Enzymatic conversion of L-histidine to urocanic acid using immobilized histidase from the rat liver]. / Fermentativnoe prevrashchenie L-gistidina v urokaninovuiu kisloty s pomoshch'iu immobilizovannoi gistidazy iz pecheni krysy.

A procedure is described for immobilization of partially purified histidase by means of covalent binding of the enzyme with amino ethyl cellulose activated by glutaraldehyde. The preparation obtained was stable within 6 months at 5 degrees and within 40 days at 39 degrees. The preparation of immobilized histidase might be used for enzymatic synthesis of urocanic acid from histidine.

[Purification, properties and regulation of urocaninase from rat liver]. / Ochistka, svoistva i reguliatsiia urokaninazy pecheni krys.

Urocaninase (EC 4.2.1.4.9) from rat liver homogenate has been purified, using protein precipitation at pH 4,8, ammonium sulfate fractionation, gel-filtration through Sephadex G-200 and chromatography on DEAE-cellulose. Upon DEAE-cellulose chromatography urocaninase is separated from the proteins possessing the activity of 3',5'-AMP-dependent protein kinase. The purified enzyme becomes activated after addition of ATP and exogenous protein kinase or one of the fractions resulting from DEAE-cellulose chromatography. Using [gamma-32P]ATP, it has been shown that such activation is accompanied by incorporation of at least one phosphate residue into the enzyme molecule. The mol. weight of urocaninase as determined by gel-filtration is about 110 000. The Km value for urocanate is 15 . 10(-6) M, the isoelectric point lies at 5,6. The mechanism of regulation of the urocaninase activity in rat liver is discussed.

[Diagnosis of histidinemia through using the determination of urocanic acid in the sweat by an enzymatic method]. / Diagnostika gistidinemii s pomoshch'iu opredeleniia urokaninovoi kisloty v pote énzimaticheskim metodom.

A diagnosis of histidinemia was confirmed by estimation of urokaninic acid in sweat using highly purified preparation of urokaninase from rat liver tissue. The content of urokaninic acid was estimated by the method developed and by means of a known chemical method, which involved reduction of urokaninic acid with zinc in a medium containing HCL; seven children with histidinemia and ten healthy children were examined. The diagnosis of histidinemia was confirmed since the content of urokaninic acid was distinctly decreased in sweat of the imparied children as compared with the control group. The method developed was highly sensitive, reproducible and accurate.

[The role of 3',5'-AMP in regulation of activity of histidase from rat liver and skin]. / Rol' 3':5'- AMP v reguliatsii aktivnosti gistidazy kozhi i pecheni krys.

A dependence of activity of histidase from rat liver and skin on the agents affecting the activity of the adenylate cyclase systeme was studied in vitro. Under conditions optimal for the activity of liver phosphorylase protein kinase the skin extract histidase was activated 2-3-fold. This is indicative of a possibility of regulation of the skin histidase activity via the adenylate cyclase system by modification of enzyme by phosphorylation-dephosphorylation, which is performed by 3':5'-AMP-dependent protein kinase. Theophylline at concentrations of 10(-4) M and 10(-3) M activates partially purified histidase (both liver and skin forms), probably in the course of direct interaction with the enzyme.

[Role of cyclic adenosine-3',5'-monophosphate in the regulation of histidase in the skin in the process of ontogeny]. / Rol' tsiklicheskogo adenozin-3',5'-monofosfata v reguliatsii gistidazy v kozhe v protsesse ontogeneza

In rat skin the histidase activity was observed 2--3 days before delivery; it was increased at the first days of postnatal development, achieving a maximal level at the 5th day and then it was decreased (within 2--3 weeks of postnatal development) to the level activity, which was found in adult animals. Concentration of urocaninic acid in skin correlated with the histidase activity. Content of urocaninic acid in skin and the histidase activity were altered under effect of administration of cylic-3',5'-AMP, dibutyryl cyclic-3',5'-AMP, glucagon, sodium fluoride, theophylline, actinomycin D and cycloheximide.