Abstract : The absolute masses of four long-lived transuranium nuclides, Am-241,Am-243, Pu-244, and Cf-249, in the vicinity of the deformed N = 152 neutron shell closure have been measured directly with the Penning-trap mass spectrometer TRIGA-TRAP. Our measurements confirm the AME2012 mass values of 241,243Am and 244Pu within one standard deviation, which were indirectly determined, by decay spectroscopy studies. In the case of the Cf-249 mass, a discrepancy of more than three standard deviations has been observed, affecting absolute masses even in the superheavy element region. The implementation of the mass values into the AME2012 network yields a reduced mass uncertainty for 84 nuclides, particularly for Pu-244 and its strongly correlated a decay chains.