Isocitrate lyase was purified from Phycomyces blakesleeanus N.R.R.L. 1555(-). The native enzyme has an Mr of 240000. The enzyme appeared to be a tetramer with apparently identical subunits of Mr 62000. The enzyme requires Mg2+ for activity, and the data suggest that the Mg2+-isocitrate complex is the true substrate and that Mg2+ ions act as a nonessential activator. The kinetic mechanism of the...

D-fructose-1,6-bisphosphate, a high energy glycolytic intermediate, attenuates ischemic damage in a variety of tissues, including brain. To determine whether D-fructose-1,6-bisphosphate serves as an alternate energy substrate in the CNS, rat hippocampal slices were treated with D-fructose-1,6-bisphosphate during glucose deprivation. Unlike pyruvate, an endproduct of glycolysis, 10 mM D-fructose...

Resistant strains of Aspergillus nidulans were obtained by one-step selection on high concentrations of various inhibitors; each strain was mutant in a different gene conferring resistance to actidione (Act), p-fluorophenylalanine (p f ) , teoquil ( te) , iodoacetate (Iod) or malachite green (mg). Some mutant alleles have been firmly, others tentatively, located. For comparative purposes attemp...

The effects of mono- and dibutyl phthalate and mono- and di(2-ethylhexyl) phthalate on energy-dependent K+ uptake, respiration rates, and succinate cytochrome c reductase activities of isolated rat liver mitochondria were evaluated. The energy-coupling processes, active K+ transport and oxidative phosphorylation, were affected most by di-n-butyl phthalate and mono(2-ethylhexyl) phthalate. Mono-...

Methoxychlor, a currently used pesticide, is a proestrogen exhibiting estrogenic activity in mammals in vivo. Methoxychlor undergoes oxidative metabolism by cytochromes P450, yielding 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M) and 1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane (bis-OH-M) as main metabolites. Since humans may be exposed to these estrogenic metaboli...

Recombinant human granulocyte colony stimulating factor (rhG-CSF) and its PEGylated product "mono-PEG20-GCSF" have already been widely used for treatment of all kinds of neutropenia. However, the high required dosage of mono-PEG20-GCSF made it relatively expensive in clinical use. We postulated that an N-terminal site-specific PEGylated rhG-CSF with higher PEG Mw (PEG30 kDa) might be able to ac...