The gene encoding this enzyme was expressed heterologously in Saccharomyces cerevisiae. In the in vitro assays (using microsomal fraction from transgenic yeast), we evaluated the preferences of mouse wax synthase towards a set of combinations of 11 acyl-CoAs with 17 fatty alcohols. The highest activity was observed for 14:0-CoA, 12:0-CoA, and 16:0-CoA in combination Bosutinib supplier with medium chain alcohols (up to 5.2, 3.4, and 3.3 nmol wax esters/min/mg microsomal protein, respectively). Unsaturated alcohols longer than 18 degrees C were better utilized by the enzyme in comparison to the saturated ones. Combinations of all tested alcohols with 20:0-CoA, 22:1-CoA, or Ric-CoA were poorly utilized by the enzyme, and conjugated acyl-CoAs were not utilized at all.
Apart from the wax synthase activity, mouse wax synthase also exhibited a very low acyl-CoA:diacylglycerol acyltransferase activity. However, it displayed neither acyl-CoA:monoacylglycerol acyltransferase, nor acyl-CoA:sterol acyltransferase activity.
We examined the kinetics of single-electron reduction of a large number of structurally diverse quinones and nitroaromatic compounds, including a number of antitumour and antiparasitic drugs, and nitroaromatic explosives by recombinant rat neuronal nitric oxide synthase (nNOS, EC 1.14.13.39), aiming to characterize the role of nNOS in the oxidative stress-type cytotoxicity of the above compounds. The steady-state second-order rate constants (k(cat)/K-m) of reduction of the quinones and nitroaromatics varied from 10(2) M(-1)s(-1) to 10(6) M(-1)s(-1), and increased with an increase in their single-electron reduction potentials (E-7(1)).
The presence of Ca2+/calmodulin enhanced the reactivity of nNOS. These reactions were consistent with an “outer sphere” electron-transfer mechanism, considering the FMNH/FMNH2 couple of nNOS as the most reactive reduced enzyme form. An analysis of the reactions of nNOS within the ‘outer sphere’ AV-951 electron-transfer mechanism gave the approximate values of the distance of electron transfer, 0.39-0.47 nm, which are consistent with the crystal structure of the reductase domain of nNOS. On the other hand, at low oxygen concentrations ([O-2] = 40-50 mu M), nNOS performs a net two-electron reduction of quinones and nitroaromatics. This implies that NOS may in part be responsible for the bioreductive alkylation by two-electron reduced forms of antitumour aziridinyl-substituted quinones under a modest hypoxia.
Sialic acid and sialyl Lewis(a/x) are found on N- and O-glycans of many human malignant cells. Carbohydrate antigens can be used selleck catalog as tumor markers, and an increase of their levels in cancer cells is associated with tumor progression. The aim of this study was to assess the level of some Lewis blood group antigens on glycoproteins in tumor (cancer tissue), intermediate zone (adjacent to tumor tissue), and normal renal cortex/medulla (uninvolved by tumor).
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