Did you create this programmatically or by GUIDE? In the last case the conversion cannot be done easily. In the fiest case it depends on the code if a merging is easier than re-writing the code from scratch.
You can extract the code to create a GUIDE designed figure easily to get the code required to create the figure: .fig files are .mat files with a changed file extension. So load() can import the .fig file: See FEX: GuideGetter
