Abstract: Calibration sleeve for extruded plastic pipes with a first layer of flexible straps that run diagonal to the longitudinal axis of the calibration device and a second layer of flexible straps, the first and second layers of straps intercross in the manner of an extendable lattice grate in which the intercrossing points are connected in an articulated manner. The first or second layers of straps are fastened in an articulated manner on an axially adjustable rigid retaining ring at the end of a calibration sleeve, and the straps of the other layer end at an axial distance from the retaining ring. Such a calibration sleeve has an inside diameter which can be adjusted precisely while taking the contraction behavior of the extruded pipe into account. The straps of the first and second layer are fastened in a stationary and in an articulated manner at the intake of the calibration sleeve.

Abstract: A peptide such as in a cell-free fermentation medium is ultrafiltered with a membrane having a molecular weight cut-off of at least approximately two times greater than the molecular weight of the peptide. The peptide is retained by the membrane, and is desalinated and concentrated to provide prepurification of the peptide. A preferred temperature for ultrafiltration is about 5 to about 15.degree. C. Permeate flow rate may be about 10 l/m.sup.2 /h to about 35 l/m.sup.2 /h, and permeate conductivity may be less than about 10 mS/cm. The permeate may be recycled until peptide concentration is constant. A cell-free fermentation medium containing hirudin from a recombinant microorganism such as Saccharomyces cerevisiae is ultrafiltered with a membrane having a molecular weight cut-off of about 20 kD to about 30 kD.

Abstract: The present invention relates to a process for inactivating Carboxypeptidase Y (CPY) in a hirudin-containing culture broth produced by fermenting a transformed yeast. It has been found that inactive precursors of CPY are activated at a temperature 70.degree. C. and that the active peptidases will further degrade hirudin when the two proteins are present together in a composition. The present invention overcomes the CPY activation problem by heating a broth containing hirudin and CPY to a temperature of about 80.degree.-100.degree. C. in about one minute or less.