proteins to peptides in proteinoussoilingssuchas spots causedby grass,blood,
fungi, faeces or food.The peptides thus produced are eithercompletelysoluble
in the cleaningsolution,or are removedwiththe washing solutionas theyare
decomposedto sufficientlysmallelements.
Savinase belongs to the serine proteases, which occur in virtually all
organisms, and which can be intracellular or extracellular enzymes. These
proteins existas two families, the trypsin-likeand the subtilisin-likefamilies. A
serineresidue, together withone aspartate and a histidineresidue, formsa
catalytictriadin whichthe nucleophilic serineO atomattacks the carbonyl C
atomof the peptide bond of the substrate to give a tetrahedral covalent
intermediate.The aspartateand histidineresidues are involved in a hydrogen
bondto the serineresidueand forma charge-relaysystem(Langeet al., 1994).
Savinase belongsto the subtilisinfamilyof serineendopeptidases, whichhave
molecular massesof 26±29kDa.Savinaseis a highlyalcalophilicmemberof the
family secreted byBacilluslentus. It consistsof 269 aminoacids, and the gene
sequence is known(Betzelet al., 1992).In the ChemicalAbstractService it is
classifiedas Subtilisin, CASNo. 9014-01-1, in the catalogue of the International
Unionof Biochemistryit is listed in the classEC 3.4.21.62. Its substrate
specificityis verybroadand it displays maximum stabilityin the pH range7 to
10 and highactivity in the range8 to 12 (Betzelet al., 1992),thuscreating
considerable interest as protein-degrading additives to detergents in the
washing-powder industry for the removalof proteinaceous soils.The crystallo-
graphic structure of Savinase is shown in Fig. 32.2(Betzel,2003).Thereare two
calciumions in the structure, whichare responsiblefor the stabilizing effectof
the subtilisin.The relativelyhighnumber of salt bridgesis likely to contribute to
its highthermal stability.The different composition of the S1 bindingloopas
Table32.1 Availableenzymesfor laboratorytests
Enzyme Type Tempera-Optimum pH Optimum Manufacturer
ture tempera- range pH
range ture
(ÎC) (ÎC)
Alcalase’ Protease <70 60 <11.5 9.0 NovoNordisk*
Savinase’ Protease <65 50 <12 9.5 NovoNordisk
Esperase’ Protease <75 60 <12 9.5 NovoNordisk
Purafect’L Protease 25±65 55 7±12 10.0 GenencorInt.**
Properase’L Protease 25±65 55 7±12 9.5 GenencorInt.
FlavourzymeTM Endoprotease/ <50 6.0 NovoNordisk
exopeptidase
CIPzymeTM Protease/ 30±75 7±11 NovoNordisk
lipase
Neutrase’ Protease 45±55 6.5 NovoNordisk
- NovoNordiskA/S, 2880 Bagsvared,Denmark(www.novonordisk.com).
** Genencor International, Inc., 925 Page Mill Road, Palo Alto, Ca 94304, USA
(www.genencor.com).
524 Handbookof hygiene controlin the foodindustry