Chymopapain. Chromatographic purification and immunological characterization.

Area of Science:

• Biochemistry
• Enzymology
• Plant Science

Background:

• Chymopapain (EC 3.4.22.6) is a cysteine proteinase found in papaya latex.
• Commercial papaya latex is spray-dried, potentially affecting enzyme composition.
• Understanding chymopapain's properties is crucial for its applications.

Purpose of the Study:

• To purify and characterize chymopapain from commercial papaya latex.
• To determine if commercial preparations contain multiple distinct forms of chymopapain.
• To confirm the identity and activity of purified chymopapain.

Main Methods:

• Purification using ammonium sulfate fractionation and Mono S cation-exchange chromatography.
• Analysis of multiple chymopapain forms using immunological techniques.
• Assessment of enzyme homogeneity, activity, and N-terminal amino acid sequencing.

Main Results:

• Chymopapain was successfully purified from spray-dried papaya latex.
• Separated chymopapain forms were immunologically identical.
• A major, homogeneous, and fully active chymopapain form with tyrosine at the N-terminus was isolated.
• Latex from unripe fruit predominantly contained a single chymopapain form.

Conclusions:

• Chymopapain is a single enzyme.
• It is distinct from other cysteine proteinases in papaya latex.
• The purification method yields a homogeneous and active enzyme preparation.