Name it. Start here... There are 21 sequences of all single amino acids. Are any of them useful? There are 21 * 20 sequences consisting of length 51 single AA with one odd on the end. Are any of them useful? Move the odd AA in on each of those again resulting in 21*20 sequences. Are any of those useful? So on and so forth.
The astute reader will note that AndrewC has disingenuously demanded that "goodusername" provide a percentage answer, when in the very next sentence (after the snippet AndrewC quoted) "goodusername" stated that a) he didn't know what the percentage was, and b) the key point was that AndrewC didn't know either and that as long as *AndrewC* doesn't know the answer, AndrewC's childish "probability analysis" attempt to attack evolution was dishonest and invalid.
Funny how AC sidestepped that very salient point, isn't it? Funny how he tried to introduce a red herring by demanding that someone else do his own homework for him, isn't it? Funny, but very typical. Red Herrings are his rhetorical specialty.
"Name it", was not meant as a demand, it was meant as a suggestion to ponder over the matter and not dismiss it in the fashion that you do. It does have a bearing on the question, obviously, since merely pouring amino acids into a beaker does not result in much of anything useful to life. There may be many useful configurations of cytochrome C that function, however the numbers being discussed are huge. Cytochrome C is a small protein consisting of 100 or so residues. The universe is thus 21100 which is also expressed as log(21) * 100 = 132.221929. Let's assume that there are 1067 sequences that are viable cytochrome C. 10-65 is rather miniscule.
1067 is fairly liberal since the earth weighs 3.59774777 × 1051 atomic mass units