Task: Data-Imputation (source dataset: tablib)

Please fill in the missing value in the input table. The missing value is denoted by '[MISSING]'. Please only return the value filled in. Do not return the whole table.

No explanation, return the value filled in JSON format: {"value": "filled_value"}. 

Input Table:
| !!SBtab TableType='rxnconReactionDefinitions' TableName='ReactionDefinitions'   | Unnamed: 1       | Unnamed: 2         | Unnamed: 3   | Unnamed: 4   | Unnamed: 5   | Unnamed: 6   | Unnamed: 7                                                     |
|:--------------------------------------------------------------------------------|:-----------------|:-------------------|:-------------|:-------------|:-------------|:-------------|:---------------------------------------------------------------|
| !UID:Reaction                                                                   | !UID:ReactionKey | !BidirectionalVerb | !MolTypeX    | !ResolutionX | !MolTypeY    | !ResolutionY | !SkeletonRule                                                  |
| phosphorylation                                                                 | p+               | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{p}                       |
| dephosphorylation                                                               | p-               | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{p} -> $x%# + $y%#$y%-{0}                       |
| auto-phosphorylation                                                            | ap+              | no                 | Protein      | component    | Protein      | residue      | $y%#$y%-{0} -> $y%#$y%-{p}                                     |
| phosphotransfer                                                                 | pt               | no                 | Protein      | residue      | Protein      | residue      | $x%#$x%-{p} + $y%#$y%-{0} -> $x%#$x%-{0} + $y%#$y%-{p}         |
| guanine-nucleotide-exchange                                                     | gef              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{GTP}                     |
| GTPase-activation                                                               | gap              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{GTP} -> $x%# + $y%#$y%-{0}                     |
| ubiquitination                                                                  | ub+              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{ub}                      |
| truncation                                                                      | cut              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{truncated}               |
| protein-protein-interaction                                                     | ppi              | yes                | Protein      | domain       | Protein      | domain       | $x%#$x%--0 + $y%#$y%--0 -> $x%!$y%#$x%--$y%                    |
| intra-protein-interaction                                                       | ipi              | yes                | Protein      | domain       | Protein      | domain       | $x%#$x%--0!$y%--0 -> $x%#$x%--[$y.locus%]                      |
| interaction                                                                     | i                | yes                | Any          | domain       | Any          | domain       | $x%#$x%--0 + $y%#$y%--0 -> $x%!$y%#$x%--$y%                    |
| protein-gene-interaction                                                        | bind             | yes                | Protein      | domain       | Gene         | domain       | $x%#$x%--0 + $y%#$y%--0 -> $x%!$y%#$x%--$y%                    |
| transcription                                                                   | trsc             | no                 | Protein      | component    | Gene         | component    | $x%# + $y%# -> $x%# + $y%# + $y.to_mrna_component_spec()%#0    |
| translation                                                                     | trsl             | no                 | Protein      | component    | mRNA         | component    | $x%# + $y%# -> $x%# + $y%# + $y.to_protein_component_spec()%#0 |
| synthesis                                                                       | syn              | no                 | Protein      | component    | Any          | component    | $x%# -> $x%# + $y%#0                                           |
| degradation                                                                     | deg              | no                 | Protein      | component    | Any          | component    | $x%# + $y%# -> $x%#                                            |
| auto-ubiquintilation                                                            | aub+             | no                 | Protein      | component    | Protein      | residue      | $y%#$y%-{0}->$y%#$y%-{ub}                                      |
| GTPase-activationincomplex                                                      | agap             | no                 | Protein      | component    | Protein      | residue      | $y%#$y%-{GTP}-> $y%#$y%-{0}                                    |
| deubiquitination                                                                | ub-              | no                 | Protein      | component    | Protein      | residue      | $x%#+$y%#$y%-{ub}-> $x%#+$y%#$y%-{0}                           |
| nuclearimport                                                                   | nimp             | no                 | Protein      | component    | Protein      | component    | $y%#$y%_[(loc)]-{0}-> $y%#$y%_[(loc)]-{nucleus}                |
| nuclear export                                                                  | nexp             | no                 | Protein      | component    | [MISSING]    | component    | $y%#$y%_[(loc)]-{nucleus} -> $y%#$y%_[(loc)]-{0}               |
| internalisation-biomolecular                                                    | int2             | no                 | Protein      | residue      | Protein      | residue      | $x%#$x%-{0} + $y%#$y%-{0} -> $x%#$x%-{int} + $y%#$y%-{int}     |
| internalisation                                                                 | int              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{int}                     |
| secretion                                                                       | sec              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{int} -> $x%# + $y%#$y%-{0}                     |
| cyclisation                                                                     | cy+              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{0} -> $x%# + $y%#$y%-{cyclic}                  |
| decyclisation                                                                   | cy-              | no                 | Protein      | component    | Protein      | residue      | $x%# + $y%#$y%-{cyclic} -> $x%# + $y%#$y%-{0}                  |



row_idx: 21
col_idx: 5
col_name: Unnamed: 5
label: Protein
output: value: Protein
tablib_key: tables/job=github_000005/batch=003598/1Bfw0_AlgFpH_4tehNg0_DV5-pey4cmB3Tm_0gWPMY4=