In a previous chromatographic study of rabbit L-myosin (Perry, 1960) the distribution of adenosine-triphosphatase activity in the main eluted fraction of this protein did not appear to be compatible with enzymic homogeneity. Brahms (1959, 1960) has also reported the separation of components of different adenosine-triphosphatase activity from rabbit myosin. The relation of these findings to the ...

Extracts of bean (Phaseolus vulgaris L.) etioplasts and chloroplasts contain a dithiothreitol-activated Ca(2+)-dependent adenosine triphosphatase which is inhibited by Dio-9. The chloroplast and etioplast enzymes have identical R(F) values upon disc gel electrophoresis. Optimum extraction of the enzyme from either plastid preparation is accomplished with 1 mm ethylenediamine tetraacetic acid. P...

1. A simple procedure involving repeated washings of actomyosin, extracted as the complex from myofibrils (natural actomyosin) at ionic strength less than 0.002, is described for the preparation of a desensitized actomyosin. 2. The Mg(2+)-activated adenosine triphosphatase of natural actomyosin was markedly inhibited by ethylenedioxybis(ethyleneamino)tetra-acetic acid, whereas that of the desen...

Culture-independent methods, employed to study the diversity and complexity of microbial communities that are based on amplification of rRNA genes with universal primers, include gradient gel electrophoresis (denaturing or temperature), single-strand-conformation polymorphism, restriction fragment length polymorphism, qPCR and highthroughput DNA sequencing. Substituting one or more base(s) with...

Human platelets diadenosine triphosphatase was characterised and compared with the Fhit protein, a human tumour suppressor with diadenosine triphosphatase activity. Both enzymes exhibit similar Km, are similarly activated by Mg2+, Ca2+ and Mn2+, and inhibited by Zn2+ and suramin. However, they are differentially inhibited by Fhit antibodies and exhibit differences in gel-filtration behaviour.

We investigated the mechanism by which inosine, a metabolite of adenosine that accumulates to . 1 mM levels in ischemic tissues, triggers mast cell degranulation. Inosine was found to do the following: ( a ) compete for [ 125 I] N 6 -aminobenzyladenosine binding to recombinant rat A 3 adenosine receptors (A 3 AR) with an IC 50 of 25 6 6 m M; ( b ) not bind to A 1 or A 2A ARs; ( c ) bind to newl...

We have tested a series of inosine analogs for their effect on germinating B. cereus 569 spores. Our results showed that although inosine (hypoxanthine nucleoside) causes spore germination by itself, the kinetic pathway exhibited complex and strongly cooperative character. Contrary to inosine’s germinating effect, the purine pathway degradation products xanthine, xanthosine, uric acid, hypoxant...

Nucleotides function in a variety of biological reactions; however, they can undergo various chemical modifications. Such modified nucleotides may be toxic to cells if not eliminated from the nucleotide pools. We performed a screen for modified-nucleotide binding proteins and identified human nucleoside diphosphate linked moiety X-type motif 16 (NUDT16) protein as an inosine triphosphate (ITP)/...

1. The preparation of a fraction containing highly purified chromaffin granules from the bovine adrenal medulla is described. 2. The fraction contains an adenosine-triphosphatase activity that is stimulated by Mg(2+) and that cannot be explained by contamination with mitochondria or microsomes. 3. It is suggested that the adenosine-triphosphatase activity is related to the uptake of cate-cholam...

1. The Ca(2+)-activated adenosine triphosphatase of heavy meromyosin is maximally stimulated by lower relative molar concentrations of phenylmercuric acetate than are required with myosin. 2. Stimulation of the Ca(2+)-activated adenosine triphosphatase of both heavy meromyosin and myosin by thiol reagents is markedly affected by ionic strength, the effects being greater with the former than wit...