Alexandria Real Estate Equities is making another major play in Boston, closing on a $168M deal for two South Boston sites.

Two plots in the Seaport, at 380 E St. and 420 E St., were sold for $168.5M to an Alexandria affiliate, according to city property records. The acquisition adds to the area’s deep pipeline of future life sciences developments.

A series of transactions revealed LLCs for the two addresses tied to New York investment firm Centerbridge Partners packaged the deal for Alexandria after Centerbridge purchased a storage facility at 380 E St. for $48M.

A representative for Alexandria in Boston declined to comment. Centerbridge and the storage facility owner, Conroy Development Group, didn’t reply to interview requests.

Alexandria made two acquisitions in August totaling $435M in the Greater Boston area for an anticipated 890K SF of development, the firm revealed in an earnings call last month, and it already plans to build up the Seaport’s emerging A Street corridor.

ARE last year partnered with National Development on a $252M acquisition of General Electric Property and is planning a 12-story, 316K SF multi-tenant life sciences facility at 5 and 15 Necco St. at the Seaport’s Fort Point neighborhood. In another ARE development, a joint venture with Anchor Line Partners is planning a six-story life sciences building at 99 A St., which is pending city approval.

In an earnings call last month, Alexandria co-CEO and co-Chief Investment Officer Peter Moglia said the Seaport was an attractive spot for opportunities.

“The amenities in the Fort Point Channel area mimic what you can find in Cambridge as well,” Moglia said, referring to the Seaport’s A Street corridor. “So we think it’s a good natural extension for those that may not have the ability to be in Cambridge but need to be close by.”

The sale shows the industry’s continued optimism in the Seaport, Colliers Managing Director for Research and Client Services in Boston Aaron Jodka said.

“We’ve seen strong investment in that category of property in the last several months,” Jodka said. “To me, that shows the confidence that investors have in our market long-term.”

Alexandria is not the only company moving now to secure life sciences development space in and around Boston. An opportunity zone fund controlled by Columbia Property Trust purchased for $48M a 1.2-acre site and adjoining parking garage not far from Cambridge's Kendall Square in a deal announced this week. The fund plans to build a life sciences facility at the future home of the MBTA's Green Line Union Square station in Somerville.

Cushman & Wakefield U.S. Research Director of Boston and America's Life Sciences Brendan Carroll said he anticipates a life sciences play in line with Alexandria’s growing portfolio. The Seaport area already touts 966K SF of laboratory construction, Cushman & Wakefield research shows.

“This does seem to be a further emergence of a laboratory, biotechnology, pharmaceutical research cluster in the Seaport district,” Carroll said. “It’s cool to see it happen in real time.”