a source of energy sufficient to heat {HEAD ~ tissue} to form {TAIL ~ a denatured proteinaceous substance}; and 
to form
a source of energy sufficient to heat { HEAD ~ tissue } to form { TAIL ~ a denatured proteinaceous substance } ; and
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH