The facile isolation of a structural phospholipoprotein from hydrogenomon as facilis and Neurospora crassa

The paper describes a new and gentle procedure for isolating "structural" phospholipoproteins from organisms and the first such isolation from a procaryotic microbe, Hydrogenomonas facilis. The amino acid composition of its protein moiety resembles that of "structural protein" from other sources. Although disc gel electrophoresis has shown the protein to be heterogeneous, this is attributed to aggregation.

New procedures for purification of L-asparaginase with high yield from Escherichia coli

l-Asparaginase is now known to be a potent antineoplastic agent in animals and has given complete remission in some human leukemias. Extensive clinical trials of this enzyme, however, were not possible in the past because of inadequate production of this substance. We have developed practical procedures for producing l-asparaginase in yields of sufficient quantity and purity for more extensive clinical evaluation. The nutritional requirements for optimal production of biologically active l-asparaginase by a strain of Escherichia coli have been ascertained. The highest yields of enzyme were obtained when cells were grown aerobically in a corn steep medium. Good enzyme production was associated with media containing l-glutamic acid, l-methionine, and lactic acid. The addition of glucose to the medium, however, resulted in depressed production of l-asparaginase. Sodium ion appeared to suppress l-asparaginase production. With the procedure described for isolation of biologically active l-asparaginase from E. coli, stable l-asparaginase preparations with a specific activity of 620 IU per mg of protein (1,240-fold purification with 40% total recovery) were obtained.

The inactivation of pea-seedling diamine oxidase by peroxidase and 1,5-diaminopentane

1. The rate of oxidative deamination of 1,5-diaminopentane by pea-seedling extracts, which contain diamine oxidase [diamine-oxygen oxidoreductase (deaminating), EC 1.4.3.6], was increased by adding pyridoxal or pyridoxal phosphate. 2. Evidence was obtained that pyridoxal does not activate the apoenzyme of diamine oxidase, but prevents the inactivation of the enzyme. 3. This inactivation only occurred when 1,5-diaminopentane was the substrate and depended on a second thermolabile factor in the extract besides the diamine oxidase. 4. Purified diamine oxidase, when catalysing the oxidation of 1,5-diaminopentane, was rapidly inactivated in the presence of peroxidase. 5. The inactivation was prevented not only by pyridoxal and pyridoxal phosphate but also by several unrelated compounds including alpha-oxoglutarate, catechol and o-aminobenzaldehyde. 6. It is suggested that peroxidase catalyses the further oxidation of the product of the oxidative deamination of 1,5-diaminopentane to a compound that inactivates diamine oxidase. 7. The results diminish the relevance of previous evidence that plant diamine oxidase contains pyridoxal phosphate.

The oxidation of Schiff bases of pyridoxal and pyridoxal phosphate with amino acids by manganous ions and peroxidase

1. Oxygen was taken up rapidly when pyridoxal or pyridoxal phosphate was added to mixtures of pea-seedling extracts and Mn(2+) ions. 2. The increases in total oxygen uptake were proportional to the pyridoxal or pyridoxal phosphate added and were accompanied by the disappearance of these compounds. 3. In addition to Mn(2+) ions, the reactions depended on two factors in the extracts, a thermolabile one in the non-diffusible material and a thermostable one in the diffusate; these factors could be replaced in the reactions by horse-radish peroxidase (donor-hydrogen peroxide oxidoreductase, EC 1.11.1.7) and amino acids respectively. 4. When pyridoxal phosphate was added to mixtures of amino acids and Mn(2+) ions oxygen uptake was rapid after a lag period of 30-90min.; the lag period was shortened to a few minutes by peroxidase, particularly in the presence of traces of p-cresol, or by light. 5. When pyridoxal replaced pyridoxal phosphate relatively high concentrations were required and peroxidase had only a small activating effect. 6. Pyridoxal or pyridoxal phosphate disappeared during the reactions and carbon dioxide and ammonia were formed. 7. With phenylalanine as the amino acid present, benzaldehyde was identified as a reaction product. 8. It is suggested that the reactions are oxidations of the Schiff bases formed between pyridoxal or pyridoxal phosphate and amino acids, mediated by a manganese oxidation-reduction cycle, and resulting in oxidative decarboxylation and deamination of the amino acids.

Activated human Hageman factor (XII)

An improved method for the isolation of highly purified active human Hageman factor has been described. An overall recovery of 25% with a purification of 10(6) has been achieved. Certain of the physical and chemical characteristics of XII have been elucidated. Selective chemical modification of functional groups and a variety of enzymatic assays have been employed in an effort to shed light on the mechanism of action of this procoagulant.

Mesenteric Chyladenectasis: Report of a Case

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