β-xylosidases catalyse the hydrolysis of short chain xylooligosaccharides from their non-reducing ends into xylose. In this study we report the heterologous expression of Aspergillus oryzae β-xylosidase (XylA) in Pichia pastoris under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The recombinant enzyme was optimally active at 55°C and pH 4.5 with Km and Vmax values of 1....

UDP-glucuronosyltransferase 1A10 (UGT1A10) is an extrahepatic enzyme expressed in aerodigestive tract tissues that exhibits significant glucuronidation activity against the important procarcinogenic benzo(a)pyrene (BaP) metabolite, BaP-trans-7,8-dihydrodiol (BPD), and the UGT1A10 codon 139 (Glu>Lys) polymorphism was previously implicated in risk for orolaryngeal cancer by Elahi et al. in their ...

We use Fabry-Perot Hα spectroscopy, complemented with published H I radio synthesis observations to derive high resolution rotation curves of spiral galaxies. We investigate precisely their inner mass distribution and compare it to CDM simulations predictions. Having verified the existence of the so-called core-cusp problem, we find that the dark halo density inner slope is related to the galax...

In an attempt to elucidate the molecular basis for the decrease in rat liver carcinogenicity and DNA-alkylating ability that accompanies deuteration of N-nitrosodimethylamine (NDMA), NDMA and its fully deuterated analogue ([2H6]NDMA) were incubated with acetone-induced rat liver microsomes. Rates for the competing metabolic routes, denitrosation and demethylation, were determined from colorimet...

copper amine oxidases (caos) catalyse the oxidative de-amination of biogenic amines which are ubiquitous compounds essential for cell growth and proliferation. the enzymes are homodimers containing both topaquinone and a cu(ii) ions as cofactors at the active site of each subunit. after extraction and purification of chickpea (cicer arietinum) amine oxidase by chromatoghraphy, km and vmax of th...

Çalışmada, toprağın katalaz enziminin kinetik parametrelerini (Vmax, KM, Vmax/KM, KSEE, [S]opt ve υ0,max) hesaplamak için H2O2 substratının farklı konsantrasyonlarında (3, 6, 9, 12, 15, 18, 21, 24, 30 %) analizler yapılmıştır. Bu parametrelerin hesaplanması analiz sonuçları kullanılarak önce hız (υ) değerleri hesaplanmıştır. Sonra ürün – substrat: [P]=f([S]) bağıntısını ifade eden modeller beli...

The kinetic behavior of the carnitine:acylcarnitine translocase was studied in isolated rat heart mitochondria. The kinetic parameters, Km(apparent) and Vmax, for carnitine were determined by measuring the rates of influx of [14C]carnitine using two different methods to quench the exchange reaction. The range of the Km(app) was 0.38-1.50 mM and the Vmax was 0.20-0.34 nmol/mg . min by both metho...

This study aimed to determine physiologically relevant kinetic and allosteric effects of P(i), AMP, ADP, and caffeine on isolated skeletal muscle glycogen phosphorylase a (Phos a). In the absence of effectors, Phos a had Vmax = 221 +/- 2 U/mg and Km = 5.6 +/- 0.3 mM P(i) at 30 degrees C. AMP and ADP each increased Phos a Vmax and decreased Km in a dose-dependent manner. AMP was more effective t...