Disable permissions inheritance on the content and copies current permissions to the content. 

This method can be accessed through the Permissions.asmx file located in:

~/Workarea/webservices/WebServiceAPI/Permissions.asmx

[SoapHeader("AuthHeader")]
[SoapHeader("RequestInfoHeader")]
[WebMethod(MessageName = "DisableContentInheritance", Description = "Deletes a user or a group from the item's permissions")]
public bool DisableContentInheritance(long id);

<SoapHeader("AuthHeader")>
<SoapHeader("RequestInfoHeader")>
<WebMethod(MessageName = "DisableContentInheritance", Description = "Deletes a user or a group from the item's permissions")>
Public Function DisableContentInheritance(id As long) As bool