Open AccessTopological location of diamine oxidase in the transverse plane of rabbit liver microsomal membranes
Author(s) -
ARGENTOCERÙ Maria Paola,
BARGAGLI Anna Maria,
SARTORI Claudia
Publication year - 1984
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1984.tb08052.x
Subject(s) - pronase , diamine oxidase , membrane , trypsin , microsome , biochemistry , cytoplasm , chemistry , incubation , proteolytic enzymes , biophysics , enzyme , biology
The transverse topology of diamine oxidase within rabbit liver microsomal membranes was studied by examining the proteolytic digestion of sealed or detergent‐permeabilized microsomal vesicles. Trypsin and pronase had no effect on diamine oxidase activity in any incubation conditions tested, while nagarse treatment reduced by 60–70% the enzymic activity of intact microsomes; no further loss of activity was observed in the presence of detergent. These results demonstrate that the active site of diamine oxidase faces the cytoplasmic membrane surface, and suggest that it does not possess or expose on either membrane surfaces bonds susceptible to the proteolytic attack by trypsin or pronase. The possible significance and the biological implications of the results are discussed.