Embodiments of probes for selectively detecting compounds having a thiol group and an amino group, e.g., cysteine and/or homocysteine, are disclosed, along with methods and kits for detecting the compounds in neutral media with the probes. The probes have a structure according to the general formula ##STR00001##
where R.sup.1-R.sup.4 independently are hydrogen hydroxyl, halogen, thiol, thioether, lower aliphatic, or lower alkoxy, x is an integer from 0 to 4, and each R.sup.5 independently is halogen, hydroxyl, thiol, thioether, lower aliphatic, or lower alkoxy. Embodiments of the disclosed probes are capable of undergoing condensation/cyclization reactions with cysteine and/or homocysteine. Cysteine and/or homocysteine can be selectively detected and identified by determining fluorescence emission of the probes at characteristic wavelengths.

The present invention provides novel cell-permeable succinates and cell permeable precursors of succinate aimed at increasing ATP-production in mitochondria. The main part of ATP produced and utilized in the eukaryotic cell originates from mitochondrial oxidative phosphorylation, a process to which high-energy electrons are provided by the Kreb's cycle. Not all Kreb's cycle intermediates are readily permeable to the cellular membrane, one of them being succinate. The provision of the novel cell permeable succinates is envisaged to allow passage over the cellular membrane and thus the cell permeable succinates can be used to enhance mitochondrial ATP-output.

The present invention relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with HDAC6, having a Formulae I or Formula II: ##STR00001## where R, L, X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, Y.sup.1, Y.sup.2, Y.sup.3, and Y.sup.4 are described herein.