A fluorogenic substrate for the continuous assaying of aryl sulfatases

Multiple Pathways for the Irreversible Inhibition of Steroid Sulfatase with Quinone Methide‐Generating Suicide Inhibitors

“…These mixtures were allowed to incubate at 22 8C and aliquots (4 mL) were removed at various time intervals and added to the wells of a 96-well microtiter plate containing 4-methylumbelliferyl sulfate (4-MUS, 196 mL, 4 mm, ca. 20 K M [5] ) in Tris (0.10 m, pH 7.0) containing Triton X-100 (0.01 %). The production of the fluorescent product, 4-methylumbelliferone (4-MU), was followed for 8 min (l ex = 360 nm, l em = 460 nm) by using a fluorimeter platereader at 22 8C.…”

“…[5] Both monofluoromethyl derivatives (1 and 3) [3] exhibited time and concentration-dependent inhibition. The inhibition occurred relatively rapidly within the first few minutes but then slowed and eventually reached a plateau as illustrated in Figure 1 A for compound 1.…”

Sulfatase-activated fluorophores for rapid discrimination of mycobacterial species and strains

“…Less explored are probes that target sulfatases (32). The hydrolysis of a sulfate ester can be used to modulate fluorescence, but the only scaffolds developed for fluorescent detection of this reaction are UV light-excited coumarins (e.g., 4-MUS) (33)(34)(35). As a commercially available fluorogenic probe for sulfatases, 4-MUS has been used extensively to assay sulfatase activity in vitro, but the high pK a of the hydrolysis product 4-methylumbelliferone (4-MU) and the high K m value of 4-MUS with most sulfatases limits its sensitivity and versatility.…”

Synthesis and evaluation of turn-on fluorescent probes for imaging steroid sulfatase activities in cells

“…12 In particular, 4-methylumbelliferyl sulfate (2, 4-MUS) is a widely used fluorogenic substrate in sulfatase assays. 19,20 We envisioned that probes 1a and 1b, which resemble compound 2 except with a fluoromethyl or difluoromethyl substituent at position C-8, could also be cleaved by STS to meet one of the most important criteria in the function of activity-based probes. Probes 1a and 1b are not innately fluorogenic.…”