[otrs] Email from OTRS to agents - How to change the address

Hello to all I need to change the email address that otrs uses to send notification to agents. I have searched in the configuration but didn't find anything, email address to receive and to send mails to customers works perfect. But I cant manage to change the "otrs@MyHost" address that the system uses to send notification to agents and now my email client has rated it as a spam. Can you help me please Thanks! Best regards Augusto García