Maximum MIMEType Length when storing type in DB

Question

What are people using as the length of a MIMEType field in their databases? The longest one we've seen so far is 72 bytes:

application/vnd.openxmlformats-officedocument.wordprocessingml.document

but I'm just waiting for a longer one. We're using 250 now, but has anyone seen a longer MIMEType than that?

Edit: From the accepted answer, 127 for type and sub-type each, so that's 254 max, plus the '/' is a limit of 255 for the combined value.