Methods for protein labeling based on acyl carrier protein

A labeled CoA type substrate of the formula (I) or (II):

• wherein R is a linker group bridging the coenzyme A and the label;
• and
• wherein R is a straight or branched chain alkylene group with 1 to 300 carbon atoms, wherein
• (a) R has at least 3 carbon atoms wherein every third carbon atom is replaced by oxygen;
• or
• (b) one or more carbon atoms are replaced by nitrogen carrying a hydrogen atom, and the adjacent carbon atoms are substituted by oxo, representing an amide function —NH—CO—;
• or
• (c) one or more carbon atoms are replaced by oxygen, and the adjacent carbon atoms are substituted by oxo, representing an ester function —O—CO—;
• or
• (d) the bond between two adjacent carbon atoms is a double or a triple bond, representing a function —CH═CH— or —C≡C—;
• or
• (e) one or more carbon atoms are replaced by a phenylene, a saturated or unsaturated cycloalkylene, a saturated or unsaturated bicycloakylene, a bridging heteraromatic or a bridging saturated or unsaturated heterocyclyl group;
• or
• (f) two adjacent carbon atoms are replaced by a disulfide linkage —S—S—;
• or a combination of two or more, especially two, alkylene and/or modified alkylene groups as defined under (a) to (f) hereinbefore, optionally containing substituents;
• and
• “Label” is a label molecule suitable for the detection and/or manipulation of a fusion protein in a system designed for detecting and/or manipulating the label.