HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mitchell, S. L. Articles by Marshall, R. T. Search for Related Content PubMed Articles by Mitchell, S. L. Articles by Marshall, R. T.

Properties of Heat-Stable Proteases of Pseudomonas fluorescens: Characterization and Hydrolysis of Milk Proteins¹

ConAgra Frozen Foods, 409 Vandiver Drive, Suite 102, Building 7, Columbia, MO 65202

R. T. Marshall

University of Missouri, Food Science and Nutrition, 122 Eckles Hall, Columbia 65211

ABSTRACT

Extracellular proteases from strains P26, 32A, PI, and P27 of Pseudomonas fluorescens were produced using a dialysis membrane method. The proteases were partially purified by gel filtration (molecular weight cutoff = 60,000) and selected biochemical characteristics were determined. Proteases of all strains were heat-stable (62.5°C, 30 min), neutral (>84% of total activity between pH 6 and 8) metalloenzymes (inhibited by 10 mM EDTA). Optimal temperature for activity was about 37°C, but all proteases were active at 5°C. Activation energies on azocasein ranged from 4.5 (P1) to 14.0 (32A) kcal·mol^–1. All extracellular proteases had strong endopeptidase activity, but no exopeptidase (aminopeptidase) activity was detected.

Proteolytic activity on purified milk proteins was measured using an o-phthaldialdehyde assay. Specific activities of the pseudomonal proteases on casein proteins were significantly higher (P<.01) than on whey proteins. Hydrolysis of whole casein by proteases of strains P26, 32A, and P27 was significantly greater than on -,ß-, or -casein, whereas protease of strain P1 hydrolyzed whole casein and -casein at equal rates. Proteases varied in abilities to hydrolyze , ß-, and -casein; bovine serum albumin, ßMactoglobulin, and -lactalbumin were weakly hydrolyzed.

¹ Contribution from the Missouri Agricultural Experiment Statical. Journal Series Number 10311.

This article has been cited by other articles:

				K. A. Frohbieter, B. Ismail, S. S. Nielsen, and K. D. Hayes Effects of Pseudomonas fluorescens M3/6 Bacterial Protease on Plasmin System and Plasminogen Activation J Dairy Sci, October 1, 2005; 88(10): 3392 - 3401. [Abstract] [Full Text] [PDF]

				C.-H. Liao and D. E. McCallus Biochemical and Genetic Characterization of an Extracellular Protease from Pseudomonas fluorescens CY091 Appl. Envir. Microbiol., March 1, 1998; 64(3): 914 - 921. [Abstract] [Full Text]