Patent ID: RE38723

Claim:
A substrate having the formula: XR-SPACER-REPORTER-BLOCK wherein BLOCK is a monovalent moiety derived by removal of a hydroxy group from phosphate or from sulfate, or biologically compatible salt thereof; or a monovalent moiety derived by removal of a hydroxy group from a carboxy group of an aromatic carboxylic acid or of an amino acid, protected amino acid, peptide, or protected peptide; or a monovalent moiety derived by removal of a hydroxy group from an alcohol or from a mono- or polysaccharide, where said BLOCK is selected to be removable from -REPORTER by action of an enzyme; -REPORTER- is an anthracene, a benzphenalenone, an acridinone , a coumarin , a fluorescein, a naphthalene, a phenalenone, a pyrene, a resorufin, a rhodol, or a rhodamine, that when no longer bound to BLOCK by a BLOCK-REPORTER bond, is fluorescent; -SPACER- is a single covalent bond, or a covalent linkage having 0-8 carbon atoms and 1-4 heteroatoms, wherein said heteroatoms, which may be the same or different, are selected from the group consisting of O, N and S; and XR— is a haloalkyl moiety, where X is a single Cl, I, or Br, and R is an alkyl linkage having 1-4 carbons.