We calculate the coupling constants of D * D s K and D * s DK vertices using the QCD sum rules technique. We compare our results with results obtained in the limit of SU(4) symmetry and we found that the symmetry is broken at the order of 40%.Keywords: Coupling constants; Form Factors; QCD Sum RuleThe knowledge of coupling constants in hadronic vertices is crucial to estimate cross sections when hadronic degrees of freedom are used. The kaon is one of the commovers light mesons that can annihilate the charmonium in a nuclear medium, given as result D and D s mesons. Therefore, the absorption of charmonium by kaons in a nuclear medium can be used to study the J/ψ suppression in heavy-ion collisions, which is one of the signatures of the formation of the quark gluon plasma (QGP) [1]. The processes of absorption of J/Ψ by kaons can be visualized in the Figure 1.To evaluate theoretically the cross section for these processes, one can use the approach based on effective SU(4) Lagrangians [2,4]. The effective Lagrangians that describe the processes represented in Fig