Longest Word Cousin

If the longest word in history is pneumonoultramicroscopicsilicovolcanoconiosis, then it's big cousin would [be] something longer, right?

Nope, something way longer:

BEHO-methionyl​threonyl​threonyl​glutaminyl​alanyl​prolyl​threonyl​phenyl​alanyl​threonyl​glutaminyl​prolyl​leucyl​glutaminyl​seryl​valyl​valyl​valyl​leucyl​glutamyl​glycyl​seryl​threonyl​alanyl​threonyl​phenyl​alanyl​glutamyl​alanyl​histidyl​isoleucyl​seryl​glycyl​phenyl​alanyl​prolyl​valyl​prolyl​glutamyl​valyl​seryl​tryptophyl​phenyl​alanyl​arginyl​aspartyl​glycyl​glutaminyl​valyl​isoleucyl​seryl​threonyl​seryl​threonyl​leucyl​prolyl​glycyl​valyl​glutaminyl​isoleucyl​seryl​phenyl​alanyl​seryl​aspartyl​glycyl​arginyl​alanyl​lysyl​leucyl​threonyl​isoleucyl​prolyl​alanyl​valyl​threonyl​lysyl​alanyl​asparaginyl​seryl​glycyl​arginyl​tyrosyl​seryl​leucyl​lysyl​alanyl​threonyl​asparaginyl​glycyl​seryl​glycyl​glutaminyl​alanyl​threonyl​seryl​threonyl​alanyl​glutamyl​leucyl​leucyl​valyl​lysyl​alanyl​glutamyl​threonyl​alanyl​prolyl​prolyl​asparaginyl​phenyl​alanyl​valyl​glutaminyl​arginyl​leucyl​glutaminyl​seryl​methionyl​threonyl​valyl​arginyl​glutaminyl​glycyl​seryl​glutaminyl​valyl​arginyl​leucyl​glutaminyl​valyl​arginyl​valyl​threonyl​glycyl​isoleucyl​prolyl​asparaginyl​prolyl​valyl​valyl​lysyl​phenyl​alanyl​tyrosyl​arginyl​aspartyl​glycyl​alanyl​glutamyl​isoleucyl​glutaminyl​seryl​seryl​leucyl​aspartyl​phenyl​alanyl​glutaminyl​isoleucyl​seryl​glutaminyl​glutamyl​glycyl​aspartyl​leucyl​tyrosyl​seryl​leucyl​leucyl​isoleucyl​alanyl​glutamyl​alanyl​tyrosyl​prolyl​glutamyl​aspartyl​seryl​glycyl​threonyl​tyrosyl​seryl​valyl​asparaginyl​alanyl​threonyl​asparaginyl​seryl​valyl​glycyl​arginyl​alanyl​threonyl​seryl​threonyl​alanyl​glutamyl​leucyl​leucyl​valyl​glutaminyl​glycyl​glutamyl​glutamyl​glutamyl​valyl​prolyl​alanyl​lysyl​lysyl​threonyl​lysyl​threonyl​isoleucyl​valyl​seryl​threonyl​alanyl​glutaminyl​isoleucyl​seryl​glutamyl​seryl​arginyl​glutaminyl​threonyl​arginyl​isoleucyl​glutamyl​lysyl​lysyl​isoleucyl​glutamyl​alanyl​histidyl​phenyl​alanyl​aspartyl​alanyl​arginyl​seryl​isoleucyl​alanyl​threonyl​valyl​glutamyl​methionyl​valyl​isoleucyl​aspartyl​glycyl​alanyl​alanyl​glycyl​glutaminyl​glutaminyl​leucyl​prolyl​histidyl​lysyl​threonyl​prolyl​prolyl​arginyl​isoleucyl​prolyl​prolyl​lysyl​prolyl​lysyl​seryl​arginyl​seryl​prolyl​threonyl​prolyl​prolyl​seryl​isoleucyl​alanyl​alanyl​lysyl​alanyl​glutaminyl​leucyl​alanyl​arginyl​glutaminyl​glutaminyl​seryl​prolyl​seryl​prolyl​isoleucyl​arginyl​histidyl​seryl​prolyl​seryl​prolyl​valyl​arginyl​histidyl​valyl​arginyl​alanyl​prolyl​threonyl​prolyl​seryl​prolyl​valyl​arginyl​seryl​valyl​seryl​prolyl​alanyl​alanyl​arginyl​isoleucyl​seryl​threonyl​seryl​prolyl​isoleucyl​arginyl​seryl​valyl​arginyl​seryl​prolyl​leucyl​leucyl​methionyl​arginyl​lysyl​threonyl​glutaminyl​alanyl​seryl​threonyl​valyl​alanyl​threonyl​glycyl​prolyl​glutamyl​valyl​prolyl​prolyl​prolyl​tryptophyl​lysyl​glutaminyl​glutamyl​glycyl​tyrosyl​valyl​alanyl​seryl​seryl​seryl​glutamyl​alanyl​glutamyl​methionyl​arginyl​glutamyl​threonyl​threonyl​leucyl​threonyl​threonyl​seryl​threonyl​glutaminyl​isoleucyl​arginyl​threonyl​glutamyl​glutamyl​arginyl​tryptophyl​glutamyl​glycyl​arginyl​tyrosyl​glycyl​valyl​glutaminyl​glutamyl​glutaminyl​valyl​threonyl​isoleucyl​seryl​glycyl​alanyl​alanyl​glycyl​alanyl​alanyl​alanyl​seryl​valyl​seryl​alanyl​seryl​alanyl​seryl​tyrosyl​alanyl​alanyl​glutamyl​alanyl​valyl​alanyl​threonyl​glycyl​alanyl​lysyl​glutamyl​valyl​lysyl​glutaminyl​aspartyl​alanyl​aspartyl​lysyl​seryl​alanyl​alanyl​valyl​alanyl​threonyl​valyl​valyl​alanyl​alanyl​valyl​aspartyl​methionyl​alanyl​arginyl​valyl​arginyl​glutamyl​prolyl​valyl​isoleucyl​seryl​alanyl​valyl​glutamyl​glutaminyl​threonyl​alanyl​glutaminyl​arginyl​threonyl​threonyl​threonyl​threonyl​alanyl​valyl​histidyl​isoleucyl​glutaminyl​prolyl​alanyl​glutaminyl​glutamyl​glutaminyl​valyl​arginyl​lysyl​glutamyl​alanyl​glutamyl​lysyl​threonyl​alanyl​valyl​threonyl​lysyl​valyl​valyl​valyl​alanyl​alanyl​aspartyl​lysyl​alanyl​lysyl​glutamyl​glutaminyl​glutamyl​leucyl​lysyl​seryl​arginyl​threonyl​lysyl​glutamyl​isoleucyl​isoleucyl​threonyl​threonyl​lysyl​glutaminyl​glutamyl​glutaminyl​methionyl​histidyl​valyl​threonyl​histidyl​glutamyl​glutaminyl​isoleucyl​arginyl​lysyl​glutamyl​threonyl​glutamyl​lysyl​threonyl​phenyl​alanyl​valyl​prolyl​lysyl​valyl​valyl​isoleucyl​seryl​alanyl​alanyl​lysyl​alanyl​lysyl​glutamyl​glutaminyl​glutamyl​threonyl​arginyl​isoleucyl​seryl​glutamyl​glutamyl​isoleucyl​threonyl​lysyl​lysyl​glutaminyl​lysyl​glutaminyl​valyl​threonyl​glutaminyl​glutamyl​alanyl​isoleucyl​methionyl​lysyl​glutamyl​threonyl​arginyl​lysyl​threonyl​valyl​valyl​prolyl​lysyl​valyl​isoleucyl​valyl​alanyl​threonyl​prolyl​lysyl​valyl​lysyl​glutamyl​glutaminyl​aspartyl​leucyl​valyl​seryl​arginyl​glycyl​arginyl​glutamyl​glycyl​isoleucyl​threonyl​threonyl​lysyl​arginyl​glutamyl​glutaminyl​valyl​glutaminyl​isoleucyl​threonyl​glutaminyl​glutamyl​lysyl​methionyl​arginyl​lysyl​glutamyl​alanyl​glutamyl​lysyl​threon