'Longest' word

'Longest' word has 189,819 letters, takes three hours to pronounce 

'Methionylthreonylthreonylglutaminylarginyl...isoleucine' is the chemical name of 'titin' (also known as 'connectin') - the largest known protein. It has 189,819 letters. 

For the word : http://www.digitalspy.co.uk/fun/news/a444700/longest-word-has-189819-letters-takes-three-hours-to-pronounce.html#~oNiQGe8jNwfpTg