Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Sonication of bovine liver microsomes completely solubilized the membrane-bound lysophospholipase II (EC 3.1.1.5). Co-chromatography with purified 125I-labelled lysophospholipase indicated that the enzyme was solubilized from microsomes in a lipid-free state. 2. In the presence of residual microsomal membranes, the solubilized lysophospholipase could only be partly degraded by trypsin (EC 3.4.21.4). Therefore, trypsin could not be used to study the transmembrane disposition of lysophospholipase in intact microsomes. 3. Chymotrypsin (EC 3.4.21.1) destroyed the solubilized lysophospholipase activity, even in the presence of residual microsomal membranes. 4. Lysophospholipase in intact microsomal vesicles was resistant to chymotrypsin digestion. 5. When microsomal vesicles were made leaky with lysophosphatidylcholine, chymotrypsin destroyed more than 95% of the lysophospholipase activity. 6. It is concluded from these experiments that at least the active center of lysophospholipase is located at the luminal side of the bovine liver microsomal membrane.
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PMID:Studies on the transverse localization of lysophospholipase in bovine liver microsomes using proteolytic enzymes. 45 32

1. Lysophospholipase activity solubilized from bovine liver microsomes could be precipitated for more than 80% by antibodies evoked in rabbits against the purified bovine liver lysophospholipase II. 2. After solubilization of the microsomes in 1.5% sodium deoxycholate, an immunoprecipitate containing lysophospholipase II in enzymically active form could be isolated. 3. Microsomal lysophospholipase activity was completely inhibited by [3H]diisopropylphosphofluoridate. Enzyme labelled in this way was isolated by immunoprecipitation from control and chymotrypsin-treated microsomes. Sodium dodecyl sulfate disc gel electrohporesis of the immunoprecipitates showed that chymotrypsin treatment of intact microsomes had no influence on the molecular weight of the enzyme. 4. Attempts to label the lysophospholipase II in microsomes by lactoperoxidase catalyzed iodination or by reaction with the diazonium salt of [125I]iodosulfanilic acid were negative, although both techniques labelled other microsomal proteins efficiently. 5. Antibody absorption experiments gave no indication for the presence of lysophospholipase antigenic sites on the outside surface of microsomes. 6. These experiments are interpreted to indicate that lysophospholipase II is exclusively located at the luminal side of the microsomal membrane.
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PMID:Studies on the transverse localization of lysophospholipase II in bovine liver microsomes by immunological techniques. 50 78