Hi,
You can try this
function pushbutton1_Callback(hObject, eventdata, handles)
% operation 1 here
guidata(hObject, handles);
function pushbutton2_Callback(hObject, eventdata, handles)
% operation 2 here
guidata(hObject, handles);
Operation 1 is performed only on click of pushbutton1 and Operation 2 is performed only on click of pushbutton2