Instanton contribution to the quark distribution functions

The instanton contribution to the quark distribution functions in the nucleon is estimated. It is shown, that taking into account the instanton induced interaction between quarks allows to explain the anomalous violation of the Ellis-Jaffe and Gottfried sum rules. The spin-dependent structure functions $g_1^p(x)$, $g_1^n(x)$, $g_1^d(x)$ are calculated in the framework of the instanton model of the QCD vacuum.