Petri nets is one of mathematical modeling languages for the description of all kind of parallel systems. Property-preserving Petri net process algebras (PPPA) were originally designed for the specification and verification of Petri net processes representing the manufacturing systems. PPPA does not need to verify the composition of Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are generalized for the newly introduced class of the P/T Petri process nets (PTPN) in this article. The only one PLACE_SUBST transformation is defined for the class of PTPN and its chosen properties are presented. The PTPN can be with the support of the PLACE_SUBST transformation easily applied into the area of design, simulation and verification of multithreading programming systems executed in parallel or distributed environment. This fact is demonstrated on the simple example of the client-server distributed programming system.