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Incoming links: Christian de Duve
Nobel lecture by Christian de Duve, delivered 12 December 1974. This is the lecture date, not an established online publication date. NobelPrize.org hosts the official document; the inspected text was a transcription on Doczz because the official PDF could not be fetched.
Official lecture PDF: www.nobelprize.org/uploads/2018/06/duve-lecture.pdf
Inspected transcription: doczz.net/doc/8221300/christian-de-duve---nobel-lecture
Cited passages: printed pp. 152–159, Figures 1–7, fractionation and enzyme latency; pp. 161–164, microscopy. This is a primary investigator’s retrospective account; it does not replace direct inspection of the original assay paper.
In the 1951 study by Jacques Berthet and Christian de Duve, liver from fasted rats was immediately chilled in an ice-cold isotonic chemical solution. The tissue was generally pressed through wire mesh; the weighed pulp was homogenized in cold sucrose using a glass Potter-Elvehjem homogenizer. Their acid phosphatase test concerned activity toward added glycerophosphate at pH : the readout was substrate hydrolysis, rather than an image of a particle.[ref]
Tissue fractionation studies. 1. The existence of a mitochondria-linked, enzymically inactive form of acid phosphatase in rat-liver tissue by Jacques Berthet and Christian de Duve. Berthet and de Duve (1951), Tissue fractionation studies. 1, printed p. 174, introduction and Methods: Fractionation of tissue constituents; inspected first-page text
Christian de Duve's retrospective describes successive centrifugation steps, separating centrifugation pellets and supernatants, and comparing enzyme distributions across the recovered fractions. Membrane disruption exposed previously inaccessible acid phosphatase activity, providing the crucial comparison with the membrane-preserving preparation. Joint fractionation patterns and release behavior of several acid hydrolases supported a shared population of digestive particles. By 1955, this evidence supported the lysosome concept.[ref]
The inference was biochemical: a barrier restricted access to active enzymes. Co-sedimentation could confuse distinct particles; a crude mitochondrial fraction did not establish residence inside mitochondria. Lysosomal enzyme latency neither images an organelle nor determines its shape. Electron microscopy of enriched fractions supplied separate morphological evidence.[ref]
Exploring Cells with a Centrifuge by Christian de Duve. Printed pp. 153–157: mixed populations and distribution patterns; pp. 161–164: incomplete separation and subsequent electron microscopy of lysosome-rich fractions
By Jacques Berthet and Christian de Duve, credited as J. Berthet and C. de Duve. Published in Biochemical Journal 50(2), 174–181, December 1951; received 28 March 1951. The received date is distinct from publication. Portland Press hosts the publisher PDF.
Inspected passage: indexed first-page text, printed p. 174, introduction and Methods, Fractionation of tissue constituents. The full original PDF and subsequent pages were not inspected; this locator does not support claims about unseen tables, numerical activity magnitudes, exact spin settings or specific disruption reagents.