Abstract: A thirty-nine amino acid peptide, Margatoxin (MgTX), is purified to homogeneity from venom of the scorpion Centruroides margaritatus. The gene encoding MgTX is constructed and this gene is expressed in E. coli, to produce recombinant MgTX. MgTX is a potent and selective inhibitor of a voltage-dependent K.sup.+ channel present in human lymphocytes. MgTX exhibits immunosuppressant activity with human T-lymphocytes, and is useful as an immunosuppressant, in modeling nonpeptidyl K.sup.+ channel blockers, and in establishing biochemical assays based on ligand binding or other protocols with which to screen for other novel modulators of voltage dependent K.sup.+ channels in lymphocytes and other tissues including the brain. As an immunosuppressant, MgTX is useful in the treatment of autoimmune diseases, the prevention of rejection of foreign organ transplants and/or related afflictions, diseases and illnesses.

Abstract: A microbiological process is described for the preparation of 6-desmethyl-6-.beta.-hydroxymethyl and 6-desmethyl-6-.beta.-carboxylovastatin derivatives and 8-acyl analogs thereof.

Abstract: L-2-oxothiazolidine-4-carboxylate, a sulfur analog of 5-oxoproline, is cleaved by the enzyme 5-oxo-L-prolinase to form cysteine, thus providing the basis for a cysteine delivery system by the addition of L-2-oxothiazolidine-4-carboxylate to base amino acid solutions or by injecting it directly into in vivo cells.

Abstract: L-2-oxothiazolidine-4-carboxylate, a sulfur analog of 5-oxoproline, is cleaved by the enzyme 5-oxo-L-prolinase to form cysteine, thus providing the basis for a cysteine delivery system by the addition of L-2-oxothiazolidine-4-carboxylate to base amino acid solutions or by injecting it directly into in vivo cells.

Abstract: The subject disclosure discloses a chemical intermediate in antibiotic synthesis of the structure: ##STR1## wherein R.sub.1 is H or OH and the asterisks indicate asymmetric carbon atoms. Compounds of this type may be obtained by fermentation with a strain of B. subtilis under aerobic conditions. Compounds of the above structure are biologically inactive but are converted by phosphorylation of the hydroxyl group to produce compounds of the structure: ##STR2## wherein R.sub.1 is H or OH, which are useful antibacterial substances having a broad spectrum of antibacterial activity.

Abstract: L-2-oxothiazolidine-4-carboxylate, a sulfur analog of 5-oxoproline, is cleaved by the enzyme 5-oxo-L-prolinase to form cysteine, thus providing the basis for a cysteine delivery system by the addition of L-2-oxothiazolidine-4-carboxylate to base amino acid solutions or by injecting it directly into in vivo cells.

Abstract: L-2-oxothiazolidine-4-carboxylate, a sulfur analog of 5-oxoproline, is cleaved by the enzyme 5-oxo-L-prolinase to form cysteine, thus providing the basis for a cysteine delivery system by the addition of L-2-oxothiazolidine-4-carboxylate to base amino acid solutions or by injecting it directly into in vivo cells.

Abstract: L-2-oxothiazolidine-4-carboxylate, a sulfur analog of 5-oxoproline, is cleaved by the enzyme 5-oxo-L-prolinase to form cysteine, thus providing the basis for a cysteine delivery system by the addition of L-2-oxothiazolidine-4-carboxylate to base amino acid solutions or by injecting it directly into in vivo cells.