title: Diversity in specificity of the extracellular proteinases in Lactobacillus helveticus and Lactobacillus delbrueckii subsp. bulgaricus.
abstract: OBJECTIVE
  To investigate the diversity in specificity of cell-bound extracellular proteinases in Lactobacillus helveticus and Lactobacillus delbrueckii subsp. bulgaricus.
  
  
  RESULTS
  HPLC analysis of whole-cell preparations of 14 Lact. delbrueckii subsp. bulgaricus and eight Lact. helveticus strains incubated with alpha (s1)-casein (f 1-23) detected at least six distinct proteolytic patterns. Differences between groups were found in both the primary and secondary specificity toward alpha(s1)-casein (f 1-23) and its breakdown products. No correlation was found between the o-phthaldialdehyde (OPA) general proteolysis analysis and alpha(s1)-casein (f 1-23) cleavage profiles.
  
  
  CONCLUSIONS
  Using the alpha(s1)-CN (f 1-23) method, six patterns of proteolysis were found in the dairy lactobacilli tested. Understanding the influence of Lactobacillus proteinase specificity on casein degradation should facilitate efforts to develop starter cultures that predictably improve the functional properties of Mozzarella cheese.
authors.affiliation: Department of Microbiology, Weber State University, Ogden, UT 84408-2506, USA. coberg@weber.edu
authors.forename: C J
authors.initials: CJ
authors.lastname: Oberg
authors.forename: J R
authors.initials: JR
authors.lastname: Broadbent
authors.forename: M
authors.initials: M
authors.lastname: Strickland
authors.forename: D J
authors.initials: DJ
authors.lastname: McMahon
mesh_terms: D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D010450:Endopeptidases / Q000378:metabolism*; D007778:Lactobacillus / Q000201:enzymology*; D013379:Substrate Specificity; D009764:o-Phthalaldehyde / Q000737:chemistry
chemical_list: D009764:o-Phthalaldehyde; D010450:Endopeptidases