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Here’s the big Google enterprise buy we’ve been telling you that’s coming.

On Thursday, Google said it is acquiring Apigee, an enterprise software company that went public last year, for $625 million.

The reason? Virtually every business is becoming more digital and more mobile. Apigee sits at the middle of this transition, providing tools for mobile APIs — i.e. reaching consumers through an app rather than a phone call — for companies like Walgreens, AT&T and Burberry.

Diane Greene, Google’s enterprise czar, described Apigee this way in a statement: “They're the hubs through which companies, partners and customers interact, whether it's a small business applying online for a loan or a point of sale system sending your warranty information to the manufacturer.”

Google wants to be this kind of hub, too. Despite its recent aggressive push around cloud storage and apps for companies, the search giant still lags behind Amazon and Microsoft in the field.

Greene’s team had been hunting for companies that could help round out her sales force and offerings. At $17.40 a share, the Apigee deal is a 6.5 premium on the smaller company’s stock price. Microsoft paid a 50 percent premium for its recent LinkedIn purchase.

We will speak with Greene later this morning about the deal.

It’s the biggest check her division has cut. It’s also the biggest buy Google has made in over two years, since its $500 million pick up of small satellite maker Skybox.