GTP cyclohydrolase I (GTPCH) catalyzes the first step in pteridine biosynthesis in Nocardia sp. strain NRRL 5646. This enzyme is important in the biosynthesis of tetrahydrobiopterin (BH4), a reducing cofactor required for nitric oxide synthase (NOS) and other enzyme systems in this organism. GTPCH was purified more than 5,000-fold to apparent homogeneity by a combination of ammonium sulfate fra...

mesoporous  mgo  microstructures  were  synthesized  using magnesium  acetate  tetrahydrate,  ammonium  oxalate  monohydrate and  pluronic  f127  via  heating  at  40  °c  for  24  h  and  subsequent calcination. the mesoporous structure of magnesium oxide with the specific  surface  area  of  47m2/g,  pore  volume  0.30  cm3/g  and  the average pore size 24 nm is produced. according to xrd stu...

Adenosine diphosphate was found to be a powerful competitive inhibitor of 5’nucleotidase partially purified from rat heart, with a greater apparent affinity for the enzyme than ATP. The inhibition imposed by either nucleotide was not relieved by a number of metabolic intermediates known to accumulate in the hypoxic heart. The enzyme required divalent cations for activity. Magnesium relieved the...

The antioxidant activity, contents of total phenolics and flavonoids were quantified in the methanolic extracts of four Ulva species(U.clathrata,U.linza,U.flexuosa and U.intestinalis) grown at different parts of northern coasts of the Persian Gulf in south of Iran.The seaweeds were collected from Dayyer,Taheri and Northern Ouli coasts in April 2011. Methanolic extracts of the seaweeds were asse...

This study aimed to determine total antioxidant and antioxidant activity of selected local varieties of lettuce (Lactuca sativa L.). Five varieties (iceberg, butterhead, romaine, green coral and red coral) were subjected to DPPH radical scavenging activity and ferric reducing antioxidant power assay (FRAP) assays for determination of antioxidant activity. Total phenolic content and total flavon...

A method for the determination of the oxygen content in magnesium and magnesium alloys has been developed. Inert gas fusion-infrared absorptiometry was modified by introducing a multistep heating process; a sample containing oxygen is fused with tin to form an eutectic mixture at 900°C in a graphite crucible, followed by a subsequent gradual temperature increase of up to 2000°C, which enables t...

BACKGROUND Ultraviolet radiation from sunlight induces overproduction of reactive oxygen species (ROS) resulting in skin photoaging and hyperpigmentation disorders. Novel whitening and anti-wrinkle compounds from natural products have recently become of increasing interest. The purpose of this study was to find products that reduce ROS in 14 Thai plant extracts. METHODS To determine total phe...

The antioxidant activity and phytoconstituents of the hydromethanolic extract of Litchi chinensis (HELC) fruit was explored in the present study. The antioxidant potential of extract has been evaluated using several antioxidant models and results were compared to standards. Fruit extract showed effective reducing power and free radical scavenging activity in a dose-dependent manner. In case o...

phosphatidate phosphohydrolase (pap) from cytosolic fraction of rat liver was purified to homogeneity having specific activity of 5.14 u/mg protein. an activity staining procedure was developed to determine molecular weight of the enzyme on polyacrylamide gel electrophoresis using ferguson plot. molecular weight (m.w.) of the active pap was 298 kda. sds-page analysis showed a m.w. of 47 kda for...