At last the deal is final. Chinese authorities have approved the $12.5 billion acquisition of Motorola Mobility by Google. And Motorola Mobility will become an integral part of Google this week.

Motorola Mobility revealed in a form filed today with Security and Exchange Commission (SEC) that Ministry of Commerce People's Republic of China (MOFCOM) has approved Google's acquisition. As a result, both the companies are planning to finalize the transaction within two business days, which counts to Wednesday this week.

Only Chinese authorities were left to give a green flag to the deal, given that both U.S. Justice Department and European Union Regulators approved the deal in February this year. The Chinese officials have finally approved the deal. However, the approval was given on a condition that Google must keep its Android OS open-source for next five years at least.

Google announced last August that the company is planning to buy Motorola for $12.5 billion. Google CEO Larry Page also said that the acquisition is meant to better protect Android from anti-competitive threats from Microsoft, Apple and other companies.

The acquisition will be Google's largest ever. The combined amount that Google paid for the rest 185 acquisitions that it has completed since going public in 2004 does not even equal to $12.5 billion it paid for Motorola. Also, it is the first time Google has taken over a company that makes smartphones and tablets. The internet search giant will also acquire 17,000 patents of Motorola Mobility Holdings Inc. giving it a strong portfolio to fight back in multiple lawsuits from rival firms like Apple and Microsoft related to Android OS and smartphones.

With a smartphone manufacturer right in the hand, Google can take the fight to the next level. It is being rumored that the company is working on a Nexus-branded device with co-partnership with either Asus or Samsung. But after the acquisition, don't be surprised to see Google release all the future Nexus-branded devices through Motorola.