Cobalamin (Cbl, vitamin B-12) has been extracted and isolated from a number of animal tissues by using (i) reverse-affinity chromatography on R protein-Sepharose followed by adsorption to and elution from charcoal-coated agarose and (ii) paper chromatography. Radioisotope dilution assays showed that only 75-97% of the Cbl chromatographed in the position of crystalline Cbl. The remaining 3-25% w...

The marine gastropod molluscs Tridachia crispata, Tridachiella diomedea, and Placobranchus ianthobapsus (Sacoglossa, Opisthobranchia) possess free functional chloroplasts within the cells of the digestive diverticula, as determined by observations on ultrastructure, pigment analyses, and experiments on photosynthetic capacity. In the light, the chloroplasts incorporate H(14)CO(3) (-)in situ. Re...

The initial procedure in the isolation of an protein, a protein complex, or a subcellular organelle is the preparation of an extract that contains the required component in a soluble form. Indeed, when undertaking a proteomic study, the production of a suitable cellular extract is essential. Further isolation of subcellular fractions depends on the ability to rupture the animal tissues in such ...

An enzyme which catalyzes the formation of nicotinamide mononucleotide in the presence of nicotinamide, S-phosphoribosylpyrophosphate, adenosine triphosphate, and Mgff has been purified from rat liver. The reaction is highly specific for ATP and is not substituted for by a variety of nucleotides. Enzymic activity has been found in all of the tissues studied, and in the crude homogenate it is ap...

Aldolase catalyzes the reversible cleavage of 1 mole of fructose-l ,6diphosphate (HDP) into 1 mole of glyceraldehyde-3-phosphate and 1 mole of dihydroxyacetone phosphate (1, 2). Although the enzyme has been obtained in crystalline form by Warburg and Christian (3) and by Taylor, Green, and Cori (4) only fragmentary data concerning the content of aldolase in different mammalian tissues have been...

Enzymes catalyzing the phosphorylation of adenosine monophosphate by adenosine triphosphate have been found in many tissues, and the adenylate kinases from liver and muscle have been extensively purified and studied (l-3). Yeast extracts also phosphorylated uridine monophosphate and guanosine monophosphate (4), and similar reactions were shown to be present in other tissues (5-7). Recently, Str...

Special Articles: The Recent Expansion of the Aluminum Industry: Absorption of Various Alcoholic Beverages: DR. T. D. JOLLY ................................. 29 HENRY NEWMAN and MASON ABRAMSON. The Production of a Pressor Substance from Serum GlobuScientific Events: lin by Action of Pepsin: DR. C. J. WEBER and Deaths and Memorials; Research at the University OTHERS. The Effect of Synthetic Vita...

The conversion of propionyl coenzyme A to succinyl-CoA involves carboxylation to methylmalonyl-Cob (a), isomerization of methyhnalonyECoA (a) to its enantiomorph methyhnalonylCoA (b), and isomerization of the latter to succinyl-CoA (3). Since methylmalonyl-CoA (a) has recently been shown to have the D configuration (4, 5), the reversible reaction catalyzed by methylmalonyl-CoA racemase will hen...

It has long been known that aqueous extracts of various animal tissues (spleen, kidney, liver, etc.) exhibit proteinase activity, which was assigned to an intracellular enzyme named cathepsin (1). The finding of peptide derivatives which serve as substrates for well defined proteinases (pepsin, trypsin, chymotrypsin) led to the use of these synthetic compounds for the study of the proteolytic a...

As reported in a previous paper (l), a new microchemical method for the determination of deoxyribonucleic acid (DNA) has been devised which permits the evaluation of DNA in amounts as small as 2.5 y per ml. The method is particularly useful with very small quantities of tissue. For this reason a study was undertaken to learn the best conditions for the application of the method to the determina...