We chose to showcase the utility of SCALP bioconjugation using the JVZ007 nanobody, which can be used for the selective targeting of the prostate-specific membrane antigen (PSMA) on prostate cancer cells. As JVZ007 has yet to be structurally characterised, the structure of JVZ007 was predicted using Phyre2. Comparison of the predicted structure of JVZ007 with the crystal structures of the nanobodies NB7 and NB37 (which also bind PSMA) revealed that many conserved residues (which are thought to mediate the binding of NB7 and NB37 to PSMA) are distal from the N-terminus of JVZ007 (Figure ). We therefore selected the N-terminus for bioconjugation and selectively introduced an α-oxo aldehyde functionality at this site. In order to demonstrate that SCALP bioconjugation could be used in conjunction with existing popular bioconjugation strategies, an azide motif was installed onto α-oxo aldehyde JVZ007 via SCALP with (4-azidophenyl)acetaldehyde 15, affording azide-JVZ007 (Figure ). Azide-JVZ007 was characterised via protein mass spectrometry and observed in several forms; the expected β-hydroxy aldehyde cross-aldol product, the corresponding hydrate, and hemiacetal (Figure ). No residual α-oxo aldehyde functionalised JVZ007 was detected by mass spectrometry after the SCALP ligation, verifying that SCALP donors with a rate of reaction comparable to phenylacetaldehyde are still reactive enough to label α-oxo aldehyde proteins. We then fluorescently-labelled azide-JVZ007 via a methodology that utilised both a copper-catalysed Huisgen cycloaddition reaction between an azide and a terminal alkyne and a copper-free strain-promoted azide-alkyne Huisgen cycloaddition between an azide and a dibenzocyclooctyne (DBCO) motif (SI, Figure ). As expected, SDS-PAGE gel analysis demonstrated only azide-JVZ007 was fluorescently labelled, whereas α-oxo aldehyde JVZ007 remained unlabelled (Figure ).