The nation’s largest publicly traded office landlord is doubling down on life sciences in one of Boston’s hottest suburbs for commercial development.

Boston Properties purchased 153 and 211 Second Ave. for $100M in cash from Montana Avenue Capital Partners, the REIT announced late last week. The two lab properties total 153K SF and are fully leased to biopharmaceutical giant Sanofi Genzyme. The properties sit near two other Boston Properties life sciences properties and add to the company’s portfolio of nearly 5M SF of office and lab space in the Waltham/Lexington region.

“Waltham continues to be a dominant urban edge location for life sciences organizations that want to attract and retain highly-educated talent,” Boston Properties Executive Vice President Bryan Koop said in a statement.

Montana Avenue Managing Partner Jeremy Rogers declined to comment Monday. The Los Angeles-based developer purchased the Second Avenue portfolio from Sanofi Genzyme in 2019 for $68.5M, Middlesex County land records show. The private firm owns a portfolio across California, Boston and Austin, Texas.

Boston Properties has ramped up life sciences investments, especially in Greater Boston and South San Francisco, catching onto the industry that shows no signs of slowing. The company has more than 3M SF leased to life sciences tenants, 2M SF of office-to-lab conversions and 4M SF of ground-up development across Cambridge, Waltham and South San Francisco, CEO Owen Thomas said in April during the firm's Q1 2021 earnings call.

Other projects by Boston Properties in Waltham include 180 City Point, a 330K SF ground-up development, 880 Winter St., a 224K SF office-to-lab conversion and 751 Gateway, a 229K SF ground-up lab development. Boston Properties claims the labs total 920K SF and $650M of its current development investments.

The suburb has matured as a commercial cluster and alternative for tenants compared to the pricier Boston and Cambridge markets. The Lexington and Waltham region has approximately 3.7M SF of lab space with rents ranging from $50 to $70 per SF, according to a 2020 Newmark report.