Tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, catalyzes the conversion of tyrosine to DOPA, Cyclic AMP-dependent protein phosphorylation conditions alter tyrosine hydroxylase activity in rat striatal homogenates. In agreement with other laboratories, we find that short-term pre-incubation (3 min) of extracts under phosphorylating conditions (Mg . ATP, cAMP) incre...

NADPH-cytochrome P-450 reductase, which catalyzes electron transfer to cytochrome P-450 in liver microsomes in reactions leading to the hydroxylation of a variety of substrates, is known to contain 1 molecule each of FMN and FAD per polypeptide chain. The spectrophotometric changes accompanying stepwise reduction of the oxidized enzyme under anaerobic conditions have recently been described. In...

Clostridium cylindrosporum formyltetrahydrofolate synthetase tetramers cross-linked with dimethyl suberimidate remained active in the absence of the monovalent cations normally required for enzymic activity and the tetrameric conformation. The modified enzyme was analyzed by sodium dodecyl sulfate electrophoresis, sedimentation velocity, and gel permeation chromatography. Under the experimental...

Enzyme catalysis has been studied as a supportive process in biochemical reactions since the 1800s. The conventional paradigm states that a catalyst accelerates a chemical reaction without affecting its equilibrium) outcome. This notion was formed by decades of analysis of biochemical catalysis under the conditions defined by Henri in 1903, which stipulate that enzyme, substrate and the enzyme-...

The exudate of fully germinated spores of Clostridium perfringens was found to contain a large amount of a spore lytic enzyme which acted directly on alkali-treated spores of the organism to cause germination. Although no detectable amount of the enzyme was found in dormant spores during germination in a KCl medium, the enzyme was produced rapidly and released into the medium. The optimal condi...

A crude extract with high proteolytic activity (78.1 EU/mL), prepared from ripe fruit of Bromelia antiacantha was used to hydrolyze and remove soft tissues from the epigyne of Apopyllus iheringi. This enzymatic extract presented four actives isoforms which have a broad substrate specificity action. Enzyme action on samples was optimized after evaluation under different conditions of pH, enzyme-...

Methyl-Coenzyme M reductase (MCR) as key enzyme for methanogenesis as well as for anaerobic oxidation of methane represents an important metabolic marker for both processes in microbial biofilms. Here, the potential of MCR-specific polyclonal antibodies as metabolic marker in various methanogenic Archaea is shown. For standard growth conditions in laboratory culture, the cytoplasmic localizatio...

A rapid, sensitive, specific and high through-put enzyme-linked immunosorbant assay (ELISA) methodfor determination of morphine in urine samples using penicillinase as label enzyme has been developed. Noextraction or chromatography was included in this assay procedure. Immunoglobulin (Ig) purified polyclonalanti-bodies against a C6-hemisuccinate derivative of morphine (M-C6-HS...

Drought is one of the most important environmental factors limiting the cultivation of ornamental plants in the green space. The effects of spermidine and salicylic acid on hollyhock (Alcea rosea L.)under drought stress were investigated. At first, the plants were sprayed with 3 doses of spermidine and 3 doses of salicylic acid (control, 100, 200 and 400 μM) for three consecut...