A method for quantitating enzyme activity of phosphorylation and dephosphorylation of a peptide or protein substrate, comprising measuring the fluorescence polarization of a fluorescence-emitting reporter molecule in solution with the phosphate. The combination of a \u201ctop closed\u201d interlock insert depression and a pair of interlock disc projections provides for better keyed alignment and a more secure connection. A valve seal support includes a radially outwardly extending flange disposed against a surface of the cylinder head external to the recessed pocket and a cylindrical body that extends into the recessed pocket. Furthermore, the characteristic value can be read out from the memory region of the component.