Thanks for your question. There are various different ways in which business conduct in Islamic countries differ from practice in the US. In fact, this is a topic that has been widely researched and written about. Although it is understandable that vast differences in protocol would arise from the East to the West.
First of all, a great difference lies in the law. The law in Islamic countries is based on the Holy Qur'an. This finds eminence in certain aspects and not in certain others. Certain things are deemed 'haram' (illegal, bad) and the things which are not haram are not taken so seriously. Therefore, the strictness in terms of rules of business is strongly alleviated in the East. It is a much more relaxed modality. In the US, that which is by the law is in no way flexible. Exports and imports in the US are also strictly regulated, making it difficult to budge. In Islamic countries, however, this is a little more flexible.
There are also differences in the set up of the financial systems in these countries. Islamic countries do not add interest to loans, where as the US does. This is just one of the differences of system.
Islamic business is also said to be much more of a verbal, face-to-face type business. Less signatures, less contracts, more giving each others word and depending on that. The US has a much more strict and 'proper' practice of making sure everything is legally correct, otherwise law suits may ensue.
I hope this answers your question!