Ficin from fig tree latex (C15-1289-862)

General description

Ficin from fig tree latex exists in multiple isoforms. The isoforms are prone to autolysis at varying temperature and tend to degrade during long term storage. It is a sulfhydryl protease with eight cysteine residues and is stabilized by three disulfide bridges.

Extinction Coefficient: E^1% = 21.0 (280 nm)
pI: 9.0

Application

Ficin from fig tree latex has been used:

• in the electron paramagnetic resonance (EPR) and steady-kinetic measurements for assessing its peroxidase functionality
• for the digestion of eye tissue sections prior to immunostaining and immunofluorescence

Biochem/physiol Actions

Ficin is classified as a thiol protease. It contains a single reactive cysteine at its active site. The amino acid homology of the active site is similar to that of papain. Ficin will cleave proteins at the carboxyl side of Gly, Ser, Thr, Met, Lys, Arg, Tyr, Ala, Asn, and Val. The reported K_m for the chromogenic substrate pGlu-Phe-Leu-p-nitroanilide is 0.43 mM. Ficin is inhibited by iodoacetamide, iodoacetic acid, N-ethylmaleimide, mercuric chloride, DFP (diisopropyl fluorophosphate), TLCK (Na-p-Tosyl-lysine chloromethyl ketone), and TPCK (N-Tosyl-L-phenylalanine chloromethyl ketone). Ficin can be used to generate high yielding F (ab′)₂ fragments from mouse IgG1.

Unit Definition

One unit will produce a ΔA₂₈₀ of 1.0 per min at pH 7.0 at 37 °C when measuring TCA soluble products from casein in a final volume of 10 mL (1 cm light path).

Physical form

Suspension in 2.0 M NaCl and 0.03 M cysteine, pH 5.0

Preparation Note

2× Crystallized