Abstract: A novel nesiritide synthetic cDNA chimera encoding human b-type natriuretic peptide (hBNP) or nesiritide and a process for the preparation of the said novel chimera. Further, the inventors disclose the use of nesiritide synthetic cDNA chimera to obtain an expressible construct to produce mature nesiritide. Particularly, the inventors disclose an application of recombinant cloning method to prepare an ORF of a nesiritide chimeric construct, which is simultaneously codon optimized for E. coli and has optimal RNA stability. The inventors also provide a process for large scale purification of nesiritide by pH precipitation and chromatography.