Victor Henri's parents were Aleksandra Viktorovna Lyapunova and Nikolay Alexandrovich Krylov, who were not married. His father was married to his mother's sister, Sofiya Viktorovna. At that time, an illegitimate child had no rights if born in Russia, but France was different: if born in France one would be a French citizen. So his parents traveled to Marseilles for his birth. After Victor Henri was born there,[3] Krylov and his legitimate wife then adopted him, and took him back to Saint Petersburg, where he lived with his father, his biological mother, and his adoptive mother. He attended a German secondary school in Saint Petersburg.
Birth certificate: Notice the annotation "parents inconnus" ("unknown parents") and the signature of Melchior Guinot, the mayor of Marseilles
In 1891, Henri entered the Sorbonne University in Paris, where he received an education in mathematics and, later, in Natural Sciences. After finishing university, he got intrigued by philosophy and psychology.
In common with several other researchers around 1900, Henri studied invertase, an enzyme that catalyses the hydrolysis of sucrose to glucose and fructose, with a view to deriving a general rate law for enzymes.[5]
Adrian John Brown, Professor of Malting and Brewing at the University of Birmingham, suggested that enzyme saturation could be understood in terms of formation of a bond between the enzyme and the substrate. Following this, and inspired by discussions with German physical chemist Max Bodenstein, Henri published the fundamental equation of enzyme kinetics for the first time.[4][6] He wrote it as follows:
(1)
where and denote the initial concentration of substrate and the concentration of product formed, respectively. The other symbols represent constants. In modern notation, it may be written as
(2)
where , and denote the reaction velocity and the substrate and product concentrations, respectively. and stand for the dissociation constants of the enzyme-substrate-complex and enzyme–product complex, respectively, and is a constant.
It took about ten years before biochemists realized the full significance of this equation. In particular, Henri's work was extended by the German biochemist Leonor Michaelis and the Canadian physician Maud Menten. They investigated invertase (saccharase) as well. In a seminal paper in 1913, they derived the equation in more detail and interpreted it more profoundly.[7] In particular, they interpreted the constants in the equation correctly and comprehensively. In particular, they recognized that considering the behaviour in the steady state at zero time with = 0 would lead to simpler and more easily interpretable results, and thus paved the way for general applications.
In most cases, the equation is used for the special case = 0 and it is usually called the Michaelis-Menten equation, and sometimes the Henri-Michaelis-Menten equation.[8] Deichmann et al. (2013) have suggested that the term Henri kinetics should be used for equation (2) in the case in which .[9]
Serge Nicolas wrote a comprehensive biographical article (in French) on Henri,[1] and a recent discussion of Henri's place in the history of enzyme kinetics, including an English translation of his thesis, is available.[10]
^According to his birth certificate, signed by Melchior Guinot, the mayor of Marseilles, he was born of unknown parents, but that was a polite fiction. As it is hardly believable that the mayor would travel across the city to register the birth of a child of unknown parents, he must have known the reality.
^V. Henri: Über das Gesetz der Wirkung des Invertins. Z. Phys. Chem. 39 (1901) 194–216
^V. Henri: Théorie générale de l’action de quelques diastases. C. R. Hebd. Séances Acad. Sci. 135 (1902) 916–919
^L. Michaelis & M.L. Menten: Die Kinetik der Invertinwirkung. Biochem. Z. 49 (1913) 333–369
^Z. Bajzer, E.E. Strehler: About and beyond the Henri-Michaelis-Menten rate equation for single-substrate enzyme kinetics. Biochem. Biophys. Res. Commun. 417 (2012) 982-985
^U. Deichmann, S. Schuster, J.-P. Mazat, A. Cornish-Bowden: Commemorating the 1913 Michaelis–Menten paper "Die Kinetik der Invertinwirkung": three perspectives. In: FEBS Journal. 2013, doi:10.1111/febs.12598