Fine structure of Streptomyces aureofaciens producing tetracycline

Subcellular localization of enzymes in Streptomyces aureofaciens and its alteration by benzyl thiocyanate. I. Phosphatases and ATP-glucokinase

Mycelia of a low- and a high-production strain of Streptomyces aureofaciens were converted into protoplasts and divided into five subcellular fractions in order to localize exopolyphosphatases (EC 3.6.1.11), triphosphatase (EC 3.6.1.25), inorganic diphosphatase (EC 3.6.1.1), apyrase (EC 3.6.1.5) and glucokinase (EC 2.7.1.2). The highest specific activity of enzymes hydrolyzing polyphosphates was found in cytoplasmic vesicles and membranes. Triphosphatase was detected in the periplasmic fraction. Periplasmic vesicles and cytoplasm exhibited a high activity of diphosphatase. Apyrase was found mainly in the fractions of membranes and cytoplasmic vesicles. Glucokinase was a cytoplasmic enzyme. The enzymes were released from membrane structures into cytoplasm or periplasmic space if benzyl thiocyanate (10 microM) was present in the growth medium.

Synthesis and degradation of proteins and DNA in Streptomyces aureofaciens

The rate of protein synthesis in Streptomyces aureofaciens, measured by incorporation of U-14C-L-leucine into cells, fluctuated during the production phase in the range of 10-15% of the values determined in the phase of intensive growth. Tetracycline partially inhibited the protein synthesis during the growth phase only. The proteins synthesized between the 6th and 18th hour of growth, were 75% degraded by the 48th hour. The DNA synthesis, measured by means of incorporation of 2-14C-thymine into the mycelium, occurred predominantly during the first 24 h of cultivation. Similarly, DNA synthesized between the 6th and 12th hour of cultivation was degraded by 75% after 48 h. The turnover of culture proteins is thus caused largely by degradation of old cells and growth of new ones which are more resistant to tetracycline. The activity of alanine aminotransferase and aspartate aminotransferase increase substantially towards the end of fermentation.