Recently I joined a newly formed Enterprise Architecture team. I've never been in on the ground floor before, so it's an interesting experience. One thing that kept coming up in our planning discussions was a need to list/record the application assets we have, who owns them, their dependencies etc. We have a lot of products at Microsoft (and a lot of internal e-mails about them). Somewhere in amongst this, I was sure I had been told Microsoft had entered this space. It turns out we did in the form of Microsoft Office Project Portfolio Server.
Application Portfolio Management is a huge topic with widely varying opinions about what features are required in a tool. Side-stepping all of that, if some of the things I've listed above would be useful for you, why not have a look at Project Portfolio Server?