Influence of cationic amphiphilic drugs on the phosphatidylcholine hydrolysis by XXXX .

@entity137 @entity37480 @entity5157 @entity4748 @entity30344 @entity4747 @entity2645 @entity8970 @entity503 @entity734 @entity23076 @entity5923
On chronic treatment certain amphiphilic drugs induce a generalized phospholipidosis. This @entity137 has been related to an inhibition of the lysosomal phospholipases due to the interaction of the drugs with phospholipids (PL). In the present experiments, the influence of the amphiphilic drugs @entity5923 , @entity2645 , @entity503 and @entity8970 on the hydrolysis of @entity4747 ( @entity4748 ) unilamellar liposomes by @entity5157 venom @entity30344 ( @entity30344 ) was studied. Special emphasis was laid on the initial phase and temperature @entity734 . The activity of @entity30344 was measured continuously with a spectrophotometric assay using @entity23076 red as indicator. In most cases a lag-phase of different duration was observed before the enzyme exhibited its full activity. The duration of the lag-phase and the rate of hydrolysis in the second phase are inversely related. The temperature @entity734 of the hydrolysis reveals a maximum of activity near the phase transition of the bilayer and a gradually decreasing activity at lower and higher temperatures, respectively. The analysis of the influence of amphiphilic drugs reveals three types of interaction. @entity2645 and @entity5923 shift the temperature activity profile towards lower temperatures without a substantial influence on the shape of the profile and on the maximal rate of hydrolysis. @entity503 inhibits the enzyme activity without any temperature @entity734 . @entity8970 , the classical @entity37480 inducing drug, exhibits a third type of interaction which seems to be a combination of the two former types.
