  We study a class of algebras B(n,l) associated with integrable models with
boundaries. These algebras can be identified with coideal subalgebras in the
Yangian for gl(n). We construct an analog of the quantum determinant and show
that its coefficients generate the center of B(n,l). We develop an analog of
Drinfeld's highest weight theory for these algebras and give a complete
description of their finite-dimensional irreducible representations.
