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Salmycin A–D, Antibiotics from Strep tomy ces violaceus, DSM 8286, Having a Siderophor‐Aminoglycoside Structure Salmycin B (2) and C (3) were isolated under acid conditions, under which they are stable, from the culture broth of Streptomyces violaceus, DSM 8286. The acid‐ and alkaline‐labile, native main component salmycin A (1), as well as salmycin D (4), were obtained under strictly neutral pH conditions. The compounds 1 (C41H70FeN7O21), 2 (C41H69FeN6O21), 3 (C40H67FeN6O21), and 4 (C40H68FeN7O21) are classified as sideromycins and are stable when dry. Mild alkaline hydrolysis of 1 and 2 yielded the known siderophor danoxamin (5; C27H46FeN5O11), and amino‐disaccharides. The amino‐glycoside 6 (C14H25NO11) of salmycin B was stabilized by hydrogenation and the structure of the corresponding peracetate 10 determined by 1H,1H‐ and 1H,13C‐correlation NMR spectroscopy (Table 1). Compound 6 consists of a glucos‐2‐ulose unit which is linked to the 2‐position of a 6‐deoxy‐6‐(methylamino)heptopyranose. The danoxamin is bonded via the carboxy group by ester linkage to the primary alcohol of the glucos‐2‐ulose. Salmycin A (1) is a natural oxime of 2, it was synthesized from 2 with hydroxylamine. The salmycins and those derivatives which contain hexapyranos‐2‐ulose form stable ketone hydrates which can be identified by mass spectrometry. Although several recently identified features of the danomycins do not correspond with those of the salmycins, 13C‐NMR spectra show that both groups of antibiotics are closely related. All salmycins, especially component 1, are highly active against Staphylococci and Streptococci, even against resistant strains of these pathogens.

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Culture fluids of Streptomyces tendae 4158 (ATCC 31210) contain a new kind of polypeptide alpha-amylase inhibitor, tendamistat (HOE 467). Several methods of isolating this inhibitor are described, including two rapid crystallisation methods, which produce homogeneous material. A characteristic of tendamistat is its tight-binding, pH-independent inhibition kinetics and the specific inhibition of the mammalian alpha-amylase form a stoichiometric 1:1 complex, which cannot be separated into its individual components by sodium dodecyl sulphate or molecular sieve chromatography. Studies of the mode of action reveal that the alpha-amylase-inhibiting activity is linked to the intact disulphide bridges of the inhibitor. It is assumed that the multipoint protein-protein bond exists between the enzyme and tendamistat. It is shown that extracellular tendamistat inhibits amylase formed by streptomyces. We therefore assume a regulatory function in the microorganism. By-products of tendamistat, which possess similar enzyme-inhibiting properties, are also described.