CHYMOSIN B FROM KLUYVEROMYCES LACTIS CONTAINING THE PROCHYMOSIN B GENE

Prepared at the 53rd JECFA (1999) and published in FNP 52 Add 7 (1999), superseding tentative specifications prepared at the 37th JECFA (1990), published in FNP 52 (1992). ADI "Not specified" established at the 37th JECFA in 1990.

SYNONYMS

Rennin, milk-clotting enzyme, chymosin, chymosin B, aspartyl protease

C.A.S. number

9001-98-3

SOURCES

Produced extracellularly by the controlled fermentation of Kluyveromyces lactis containing the bovine prochymosin B gene. The fermentation broth is adjusted to pH 2 to convert prochymosin to chymosin, which also kills the production cells. Chymosin is separated from the cell material by filtration and further purified by clarification with diatomaceous earth followed by several cellfiltrations and one ultrafiltration.

ACTIVE PRINCIPLES

Chymosin

SYSTEMATIC NAMES AND NUMBERS

None (EC 3.4.23.4)

REACTIONS CATALYZED

Cleaves a single bond in kappa-casein

DESCRIPTION

Clear, colourless or slightly coloured aqueous solutions containing the active enzyme

FUNCTIONAL USES

Enzyme preparation
Used in clotting of milk for cheese production

GENERAL SPECIFICATIONS

Must conform to the General Specifications for Enzyme Preparations used in Food Processing (FNP 52 & Addendum 6)

CHARACTERISTICS

IDENTIFICATION

Milk clotting activity (FNP 5)

The sample shows milk clotting activity

	Prepared at the 53rd JECFA (1999) and published in FNP 52 Add 7 (1999), superseding tentative specifications prepared at the 37th JECFA (1990), published in FNP 52 (1992). ADI "Not specified" established at the 37th JECFA in 1990.
SYNONYMS	Rennin, milk-clotting enzyme, chymosin, chymosin B, aspartyl protease
C.A.S. number	9001-98-3
SOURCES	Produced extracellularly by the controlled fermentation of Kluyveromyces lactis containing the bovine prochymosin B gene. The fermentation broth is adjusted to pH 2 to convert prochymosin to chymosin, which also kills the production cells. Chymosin is separated from the cell material by filtration and further purified by clarification with diatomaceous earth followed by several cellfiltrations and one ultrafiltration.
ACTIVE PRINCIPLES	Chymosin
SYSTEMATIC NAMES AND NUMBERS	None (EC 3.4.23.4)
REACTIONS CATALYZED	Cleaves a single bond in kappa-casein
DESCRIPTION	Clear, colourless or slightly coloured aqueous solutions containing the active enzyme
FUNCTIONAL USES	Enzyme preparation Used in clotting of milk for cheese production
GENERAL SPECIFICATIONS	Must conform to the General Specifications for Enzyme Preparations used in Food Processing (FNP 52 & Addendum 6)
CHARACTERISTICS
IDENTIFICATION
Milk clotting activity (FNP 5)	The sample shows milk clotting activity