Immobilized metal ion affinity chromatography in enzyme fractionation.

Ribitol dehydrogenase from Mycobacterium butyricum and alpha-mannosidase from Lupinus luteus seedlings were fractionated by the immobilized metal ion (Cu2+ or Zn2+) affinity chromatography (IMAC) on iminodiacetic acid coupled to Sepharose 6B. In a single step, ribitol dehydrogenase was purified 10-12 fold with the recovery above 80% when using Zn(2+)-Sepharose 6B as the sorbent and decreasing linear gradient of pH from 7 to 4. In the same conditions purification of alpha-mannosidase was less effective (2-3 fold, recovery 60-70%).

The hypoglycaemic response of diabetic rats to insulin-liposomes.

We prepared insulin-liposomes using one combination of lipids including phosphatidylcholine (cholesterol) stearylamine, 7/2/1 (molar ratio). Non-sonicated liposomes (LMV) and sonicated liposomes (SUV) contained about 20% and 5% of insulin, respectively. Free insulin was removed from liposomes-associated insulin by ultracentrifugation, or ultrafiltration on Sepharose 6B column.

Hypoglycemic effect of liposome-entrapped insulin administered by various routes into normal rats.

We entrapped insulin into liposomes using one combination of lipids comprising egg lecithin-cholesterol-stearylamine (7:2:1 molar ratio). The efficiency of entrapment was about 20% with unsonicated liposomes (LMV), and around 5% with sonicated liposomes (SUV). LMV-, SUV- and free-insulins were administered via different routes into male, non-diabetic Wistar rats in order to change the glycemia.

A study on the Prethcamide hydroxylation system in rat hepatic microsomes.

Ethyl butamide and propyl butamide, the active constituents of the analeptic drug named Prethcamide (Ciba-Geigy), undergo biotransformation to respective single metabolites in the presence of rat hepatic microsomes and the NADPH-generating system. Spectral analysis showed that the metabolites were hydroxylated forms of the drug. The hydroxylation was stimulated by NADH and increased ionic strength, and inhibited by the known cytochrome P-450 inhibitors, e.

The possible occurrence of zinc in ribitol and sorbitol dehydrogenases from Mycobacterium sp. 279.

The activity of polyhydric alcohol dehydrogenases in Mycobacterium sp. 279 was studied under limitation of zinc in the growth medium. It was found that the activity of ribitol and sorbitol dehydrogenases were markedly lowered and that of D-arabinitol dehydrogenase remained unchanged in the Zn2+-deficient cells.