The term "amyboid" refers to a pathologic proteinaceous substance (24, 38) deposited cxtraceblubarly in tissue and most commonly identified by light microscopy as a homogeneous eosinophilic material which stains with alkaline Congo red (7, 65). These deposits may be restricted to a single tissue Infrared spectroscopy: Samples were prepared for infrared spectroscopy as films cast onto thin silver chloride discs from either distilled water or (in the case of the V1 fragments) 50% formic acid solution and dried at 35#{176}C in vacuo. Amyboid fibrils were also

"Amyloid" fibrils have been created from some human Bence Jones proteins by proteolytic digestion under physiologic conditions. These fibrils with an antiparallel, beta-pleated sheet conformation consist of only a portion of the variable region of the immunoglobulin light polypeptide chain and share the physical properties of amyloid fibrils. The relation between amyloidosis and immunoglobulins is thus more firmly established and a pathogenetic mechanism for amyloid fibril formation is suggested.

A B S T R A C T This report suggests a mechanism for collagen degradation mediated by human granulocytic leukocytes. A specific collagenase, which is extractable from human granulocytes, has been partially purified by DEAE chromatography. This collagenolytic enzyme is operative at physiological pH and is inhibited by EDTA, cysteine, and reduced glutathione but not by human serum. The enzyme cleaves the collagen molecule into two specific products, without loss of helical conformation. Electron micrographs of segment long spacing aggregates indicate that the cleavage occurs one-quarter of the length from the carboxy terminal end of the molecule. Experiments with crude extracts from granulocytes suggest that the specific products of granulocyte collagenase activity are then degraded by other proteases present in the human granulocyte.

No abstract