Gerardus Johannes Mulder or Gerrit Jan Mulder (27 December 1802 – 18 April 1880) was a Dutch organic and analytical chemist. Life Mulder was born in Utrecht and earned a medical degree from Utrecht University. He became a reader of chemistry in Rotterdam and in 1840 he was appointed professor at Utrecht University. Protein Following a suggestion by Jöns Jacob Berzelius, Mulder used the term protein in his 1838 paper, "On the composition of some animal substances" (originally in French but translated in 1839 to German). In the same publication, he also proposed that animals draw most of their protein from plants. Mulder "was the first to propose a theory concerning the causes of the differences between albumin, casein, and fibrin, and other substances more or less similar to them in physical properties and in their chemical behavior when exposed to reagents. Analyses of these substances showed that their percentage contribution with respect to carbon, hydrogen, nitrogen and oxygen were so similar as to suggest that they contain one common radical." This radical, a macromolecule, had formula C20 H31 N5 O12 , and was known as protein. The variations in albuminous substances were attributed to peripheral bonds of protein to sulfur and/or phosphorus. Justus Liebig and his students sought to determine the structure of proteins, but until the methods of Emil Fischer and Franz Hofmeister became available, the amino acid decompositions were unknown. Augustus Voelcker was Mulder's assistant for a year from 1846. In 1850, Mulder was elected a foreign member of the Royal Swedish Academy of Sciences. He died in Bennekom. References Ihde, Aaron (1964) The Development of Modern Chemistry, Harper and Row, pages 359 and 423–424. External links On the composition of some animal substances Translation of parts of Mulder's article from: Mikulás Teich, A Documentary History of Biochemistry, 1770-1940 (Rutherford, NJ: Fairleigh Dickinson University Press, 1992) 1802 births 1880 deaths Scientists from Utrecht (city) Organic chemists Dutch biochemists Dutch natural scientists Members of the Royal Netherlands Academy of Arts and Sciences Members of the Royal Swedish Academy of Sciences Academic staff of Utrecht University