A deoxyribonuclease distinct from the previously isolated asparagus ribosome-inactivating proteins, possessing a molecular weight of 30 kDa and requiring a pH of 7.5 for optimum hydrolytic activity toward herring sperm DNA, was isolated from Asparagus officinalis seeds. The isolation procedure involved extraction with saline, (NH(4))(2)SO(4) precipitation, ion-exchange chromatography on DEAE-ce...

Although several nit.ro-reductase systems, either from animals or microorganisms, have been identified in intact cells or cell-free homogenates, partial purification of the enzymes has been reported only for extract.s of Neurospora crassa (1) and Aspergillus niger (2, 3). Purification of the enzyme or enzymes involved in the reduction of organic nitro compounds is important for two reasons. (a)...

Calcitonin was extracted from the ultimobranchial gland of salmon in quantities sufficient to permit purification and chemical characterization. The partially purified extract was subjected to gel filtration and ion exchange chromatography. Purification was monitored by bioassay of column e&tents against a standard prepared from the starting material. These methods led to detection of two chemi...

Seventeen peptides have been isolated from a tryptic digest of soluble elastin by ion exchange chromatography and gel filtration. Molecular weights range from approximately 1,700 to 10,500. Partial or complete amino acid sequences of the peptides were obtained and provide the first extensive data on the primary sequence of elastin. Several important findings stand out. First, the sequences obta...

The fundamental importance of human milk in infant nutrition makes it desirable to have available as complete information as possible on the amounts of amino acids contributed to the diet from this source (Williamson (l), Block and Bolling (2, 3), and Macy (4)). In the present study, hydrolysates of human milk have been analyzed by ion exchange chromatography (Moore and Stein (5)) as applied in...

Ammonium sulfate is one of the subsidiary components in the stealth liposome structure. The ratio of ammonium ion bound to liposome sphere to ammonium ions outside the liposome plays an important role in drug delivery formulation; accordingly, in order to quantify the ammonium ion in the liposome structure, a rapid and sensitive method was validated using a conductivity detector. Through this m...

Simian pituitary growth hormone was prepared in homogeneous form by sequential application of exclusion chromatography on Sephadex G-100, ion exchange chromatography on diethylaminoethyl Sephadex with a single eluent, and density gradient column electrophoresis. DEAESephadex chromatography with a single eluent was also used to separate two biologically active components of human pituitary growt...

pH gradient protein separations are widely used techniques in the field of protein analytics, of which isoelectric focusing is the most well known application. The chromatographic variant, based on the formation of pH gradients in ion exchange columns is only rarely applied due to the difficulties to form controllable, linear pH gradients over a broad pH range. This work describes a method for ...

Two ion chromatographic methods have been proposed for the simultaneous determination of caffeine, theobromine and theophylline. The separations were based on isocratic elutions and the determinations on ultraviolet absorbance detections at 274 nm. The detection limits (signal-to-noise ratio 3:1) for the three compounds were all below sub-mg mlÿ1 level. The methods have been successfully applie...

The cytokinin complex of Datura innoxia Mill. crown gall tissue was purified by ion exchange, Sephadex LH-20 chromatography and reversed-phase high performance liquid chromatography. By gas chromatography-mass spectrometry using (2)H-labeled compounds, the following cytokinins were identified in the basic fraction eluting from a cation exchange column: zeatin, zeatin riboside, dihydrozeatin, di...