Serum butyrylcholinesterase of non-human primate shows amine sensitive aryl acyl amidase and metallopeptidase activities and characteristics similar to those of the human serum enzyme.

Butyrylcholinesterase (BChE) was purified from monkey serum and the catalytic activities were examined. The enzyme has a molecular mass of approximately equal to 74 kDa as seen by SDS-gel electrophoresis. Monkey serum BChE also exhibits an amine sensitive aryl acylamidase (AAA) and a metallocarboxypeptidase activity. The tyramine activation of the aryl acylamidase activity and the metal chelator inhibition of the peptidase activity were characteristics similar to those of the human enzyme. Studies on 65Zn2+ binding and zinc chelate Sepharose chromatography showed that monkey serum BChE and human serum BChE have similar characteristics. Limited alpha chymotrypsin digestion of monkey serum BChE followed by Sephadex gel chromatography cleaved the enzyme into a 36 kDa fragment exhibiting peptidase activity. However the 20 kDa fragment corresponding to cholinesterase and aryl acylamidase activity was not detectable possibly due to the unstable nature of the fragment. Immunological studies showed that a polyclonal antibody against human serum BChE cross reacted with monkey serum BChE. The identical nature of the catalytic activities of human serum BChE and monkey serum BChE supports the postulate that all three catalytic activities co-exist in the same enzyme. This is the first time that purification and characterisation of the monkey serum BChE which has the highest sequence identity and immunological identity with that of human serum BChE, is being reported.

Dynamics of Met5- and Leu5-enkephalin and their receptor binding activity in relation to morphine.

A complete normal coordinate analysis of Met5- and Leu5-enkephalins using Wilson's GF matrix method and Urey Bradley force field has been carried out to understand the dynamical behaviour of enkephalins. In addition, the charge distributions on different atoms of the two enkephalins and morphine using CNDO/2 method are also reported. The similarity in the charge distribution on the part of these two molecules is indicative of the possible interactions at the same receptor site as that of morphine and its derivatives. Apart from the topographical features and charge distribution, binding onto receptor site is not a static but a dynamic process and low frequency modes must play an important role in the recognition process. The significance of the out-of-plane amide VII band and other skeletal modes as characteristic of conformational states of Met5- and Leu5-enkephalins are discussed.

Efeitos das encefalinas sobre o aparelho digestivo / Enkephalins effects on digestive system

A identificaçäo, localizaçäo e propriedades digestivas das encefalina-metionina e encefalina-leucina säo discutidas neste artigo. Interaçöes sinérgicas e antagônicas säo também apresentadas.