in an - La ▁Union ▁Express way ), ▁express way ▁route ▁in ▁the ▁Philippines . ▁ ▁E 1 ▁express way ▁( P ak istan ) ▁ ▁Science ▁and ▁mathematics ▁▁ ▁Ex pon ential ▁integral , ▁, ▁mathematical ▁function ▁ ▁the ▁E 1 ▁series ▁( number ▁series ) ▁of ▁preferred ▁numbers ▁ ▁Bio chem istry ▁▁ ▁E 1 ▁( H CV ), ▁a ▁vir al ▁struct ural ▁protein ▁found ▁in ▁he pat itis ▁C ▁ ▁E 1 , ▁a ▁un im ole cular ▁elim ination ▁mechanism ▁in ▁organ ic ▁chem istry ▁ ▁E 1 - enz ym es , ▁also ▁known ▁as ▁U bi quit in - activ ating ▁en zym es , ▁an ▁en zym e ▁which ▁catal y zes ▁the ▁first ▁step ▁in ▁the ▁u bi quit ination ▁reaction , ▁which ▁targets ▁a ▁protein ▁for ▁de grad ation ▁via ▁a ▁prote as ome ] ▁ ▁E 1 ▁regul atory ▁sequence ▁for ▁the ▁ins ul in ▁gene ▁ ▁E str one , ▁a ▁h orm one ▁ ▁Py ru v ate ▁de h ydro gen ase ▁( E 1 ), ▁the ▁first ▁component ▁en zym e ▁of ▁py ru v ate ▁de h ydro gen ase ▁complex ▁ ▁A ci re duct one ▁synth ase , ▁an ▁en zym e ▁ ▁H ap lo group ▁E 1 ▁( Y - D NA ), ▁a ▁human ▁Y - chrom os ome ▁DNA ▁ha p lo group ▁ ▁Medicine ▁▁ ▁E 1 - is op rost ane , ▁a ▁type ▁of ▁is op rost ane