  In this paper, we study and compare the optical and X-ray counterparts of
subparsec supermassive black hole binaries (SMBHBs). With that aim, we
simulated the profiles of optical spectral lines emitted from the broad line
region (BLR) as well as X-ray spectral lines emitted from the relativistic
accretion disks around both black holes and compared them with each other. The
obtained results showed that SMBHBs could cause a specific, but different
variability of the lines from the optical part and Fe K$\alpha$ line, leaving
potentially detectable imprints in their profiles. Since these imprints depend
on the orbital phase of the system, they could be used for reconstructing the
Keplerian orbits of the components in the observed SMBHBs. Moreover, such
signatures in the optical and X-ray line profiles of the observed SMBHBs could
be used as a tool for the detection of these objects as well as for studying
their properties.
