The enzymic formation of enzyme-bound amino acyl adenylates from adenosine triphosphate and amino acid (Equation 1) has been recognized for several years (l-8) and enzymes specific for certain of the amino acids have been isolated in a number of laboratories (2, 9, 10). These same enzymes are now known (11-15) to catalyze a second reaction involving the transfer of the amino acyl moiety from th...

The genes for tranfer ribonucleic acid (tDNA) and 5S ribonucleic acid (5SDNA) were isolated from the total deoxyribonucleic acid (DNA) of Escherichia coli. The relatedness of tDNA and 5S from E. coli and other species of Enterobacteriaceae was determined by reassociation of the isolated genes labeled with 32PO4 to unlabeled, unfractionated DNA. Double-stranded DNA was separated from unreacted D...

Preparations of nucleic acids obtained by extraction of mouse liver, HeLa cells and cell fractions with phenol and deoxycholate have been characterized with regard to the differential solubility of ribonucleic acid and deoxyribonucleic acid in ethanol, density-gradient centrifugation and the presence of high-molecular-weight contaminants. Ribonucleic acid obtained by this method is less soluble...

Threonyl ribonucleic acid synthetase was purified 400-fold from rat liver. During stepwise chromatography on diethylaminoethyl cellulose, two fractions with this enzymatic activity were observed. The separated fractions give distinct elution patterns on rechromatography on the same ion exchanger. Threonyladenylate-enzyme complex prepared with 14Cthreonine and 3H-adenosine triphosphate shows a s...

A number of recent investigations have been concerned with the relative localization of ribonucleic acid and of protein-synthetic processes within specific structural components of cells (l-9). The results thus far have shown that, after incorporation of radioactive amino acids in vivo or in vitro, the radioactivity is concentrated mainly in the small cytoplasmic particles called microsomes. Pr...

INTRODUCTION ................ ................................ 483 DISCOVERY OF REOVIRUSES .............................................. 483 STRUCTURE OF THE REOVIRUS PARTICLE .................. ............. 484 REOVIRUS GENOME ................................................ 484 PROTEINS OF REOVIRUS ................................................ 486 INFORMATION CONTENT OF THE 10 REOVIRUS G...

Streptococcal DNAse C is more resistant to heat inactivation than the A or B enzyme. DNAses A and C are indifferent to the bacterial ribonucleic acid inhibitor whereas the B enzyme is markedly inhibited. Prolonged digestion with relatively large amounts of DNAse B results in chemical and biological destruction of the inhibitor. Ribonuclease as well as deoxyribonuclease activity is associated wi...

During an attempt to purify a leucine-activating enzyme from pig-liver-protein fractions low in 'soluble' ribonucleic acid (Hele & Finch, 1960), some fractions became very unstable and lost over half their activity when kept overnight at 15°. In some instances, enzyme activity has been found to be preserved by the presence of 'soluble' ribonucleic acid. In this paper the effect has been further...

The discovery of enzymes which catalyze the deoxyribonucleic acid-dependent synthesis of ribopolynucleotides (l-6) stimulated an immediate inquiry into the role played by DNA in thisunique reaction. The speculation that DNA might serve as a template for the polymerization of ribonucleotides into a complementary ribonucleic acid molecule was confirmed by studies from a number of different groups...