Ribonuclease activation volume

In a measurement of a hydrophobic activation volume, Kettman et al. (1966) found a large positive volume change when ribonuclease molecules with attached polyvalyl chains were made to aggregate under pressure. Work is also in progress on the interaction kinetics... 

Cell walls, total membrane-bound components, and ribosomes were separated and assayed for cellulase activity to study the subcellular localization of the enzymes as follows. Segments (approx. 5 g fresh wt) were ground in two volumes of extraction medium containing 0.4M sucrose (ribonuclease-free), 5mM Mg acetate, lOmM Tris-HCl (pH 7.5 at 22°C), 20mM KC1 and 5mM / -mercaptoethanol. The brei was filtered and the filtrate centrifuged at 500 Xg for 20 min. The post-500 Xg supernatant was fractionated essentially as previously described (28). Aliquots (7 mL) of the supernatant were layered on a discontinuous gradient composed of 2 mL 70% (w/v) sucrose and 3 mL 15% (w/v) sucrose both in lOmM Tris-HCl (pH 7.5 at 22°C), lOmM KC1, 2.5mM Mg acetate and ImM / -mercaptoethanol. The tubes were centrifuged at... 

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