  Relying on the classification of simple Lie algebras over algebraically
closed fields of characteristic $>3$, we show that any finite-dimensional
central simple 5-graded Lie algebra over a field $k$ of characteristic $\neq
2,3$ is a simple Lie algebra of Chevalley type, i.e. a central quotient of the
Lie algebra of a simple algebraic $k$-group. As a consequence, we prove that
all central simple structurable algebras and Kantor pairs over $k$ arise from
5-gradings on simple Lie algebras of Chevalley type.
