Isolation and some properties of phospholipase D from Bacillus subtilis G-22]

A method of isolating highly purified phospholipase D from Bac. subtilis G-22 is described. It includes ammonium sulphate fractionation, thermal denaturation, chromatography on lipoprotein bound with sepharose 6B and AH-sepharose 4B. The enzyme is 130-fold purified, its yield exceeds 90.0%, its specific activity is 164 units per mg of protein. The homogeneity of the enzyme is demonstrated by polyacrylamide gel electrophoresis, ultracentrifugation, isoelectric focusing and N-terminal amino acid determination by means of dinitrophenylation and dancylation. Proline is found to be N-terminal amino acid. The molecular weight of the enzyme, as determined from gel filtration through Sephadex G-100, is 21500 +/- 300, its sedimentation constant is 1.4S, isoelectric point is at pH 4.2. The molecular weight calculated from amino acid composition, is 21000--22000. Polypeptide chain contains of 196--205 amino acid residues. Phospholipase D develops its maximal activity at pH 8.5 and does not contain free SH-groups. Benzylsulphofluoride does not inhibit the enzyme activity. Phospholipase D is activated by Cd2+, Co2+, Zn2+, Ca2+ and is inhibited by EDTA, pIi50 being about 2.6.     

Thiocyanate ion formation in rapeseed meals.

Meal prepared from unheated rapeseed (Brassica napus cv. Zephyr) showed the presence of t,iocyanate ion, while meal from heated seed of the same cultivar did not show detectable amounts. Unheated seed meal on autolysis, and heated seed meal on incubation with thioglucosidase, yielded increased amounts of thiocyanate ion. Various commercial rapeseed meals showed the presence of t,iocyanate ion only after enzyme incubation. Low glucosinolate, cv. Bronowski, and higher glucosinolate, cv. Zephyr on enzymic incubation yielded comparable amounts of thiocyanate ion, suggesting that the precursor responsible in the two varieties was the same and present in similar quantities. No formation of thiocyanate ion was observed on incubation of sinigrin with thioglucosidase. Rats dosed with heated meal, containing intact glucosinolate, showed a slight increase of thiocyanate ion in the urine as compared with control rats dosed with water, while a relatively large increase followed dosing with sinigrin. Rats dosed with meal containing free thiocyanate ion excreted the ingested thiocyanate ion almost quantitatively.     

Photoelectric signals from dried oriented purple membranes of Halobacterium halobium

In dried oriented samples of purple membrane isolated from Halobacterium halobium, the photoelectric activity decreases and the light adaptation vanishes when the water content of the sample is lowered. In the photocycle the first steps of the proton movement were accelerated with decreasing humidity, while the last steps of the photocycle could not be observed. From the analysis of the photoelectric signal we conclude that at low humidities the protons move forward in the L decay and return to their original place during M decay.     

Seraspenide (acetylSDKP): phase I-II trial study of inhibitor of hematopoiesis protects against toxicity of aracytine and ifosfamide monochemotherapies]

Seraspenide, a synthetic tetrapeptide, inhibits cell cycle entry of normal hematopoietic stem cells. In mice it protects hemopoiesis against the damage caused by cytarabine, cyclophosphamide and carboplatin. Seraspenide has been given to 53 cancer patients undergoing monochemotherapy with cytarabine and ifosfamide in a double-blind cross-over randomized study. A significant protection of peripheral blood cells has been observed. Seraspenide has been devoided of toxicity.