rīˈzäptərə̇n noun
( -s )
Etymology: rhiz- + pterin
: a pale yellow crystalline aldehydo amino acid C 15 H 12 N 6 O 4 obtained in the fumaric acid fermentation by a black mold ( Rhizopus nigricans ) that promotes the growth of several streptococci : a formyl derivative of pteroic acid