Is there a Pullulanase in Escherichia coli?

Abstract

No pullulanase activity could be detected in maltose-grown cultures of 11 different strains of Escherichia coli. Neither these strains, nor 40 other strains of the same species would grow on pullulan, while all of them grew on maltose and some were shown to grow on maltotriose the exclusive product of pullulanase action on pullulan. These results are in contradiction with those reported last year in this journal by Palmer, Wober and Whelan. On the other hand pullulanase activity could be detected, as reported by Bender and Wallenfels in 1966, in two strains of Aerobacter aerogenes.Pullulanase is an amylopectin and glycogen debranching enzyme produced by certain bacteria such as Aerobacter aerogenes and Streptococcus mitis [i-31. Its name is derived from that of its most convenient substrate, pullulan, a linear polysaccharide produced by the fungus Pullularia pullulans, and composed of about 480 maltotriose units linked by 01-1,6 glycosidic bonds [4].In a recent paper [5] Palmer et al. report the occurrence of a pullulanase in Escherichia coli strain ML. They claim that the enzyme is induced during growth on maltose, and that it is located in the outer membrane of the bacterial envelope. When pregrown on maltose, E. coli ML is reported to grow on pullulan. To us, these observations were of considerable interest, mainly because recent results from our laboratory demonstrate that a maltose-induced protein of the outer membrane constitutes the receptor for bacteriophage lambda [6]. Although apparently not involved in the metabolism of maltose, this protein is coded by a gene located in one of the maltose operons [7]. The possibility existed that pullulanase was the phage receptor. Unfortunately phage lambda does not adsorb onto E. coli ML cells (our unpublished results) and no pullulanase activity can be found in E. coli K12, the standard host for bacteriophage lambda (Palmer and Wober, personal communication). Still we proceeded to look for a strain of E . coli which might a t the same time have a pullulanase and adsorb phage lambda. The result of this search, summarized in this paper, is that we were unable to find physiological or biochemical evidence for the occurrence of a pullulanase in any strain of E. coli, including E. coli strain ML.

The MalT-dependent and malZ-encoded Maltodextrin Glucosidase of Escherichia coli Can Be Converted into a Dextrinyltransferase by a Single Mutation

“…MalZ, even though exhibiting ␥-cyclodextrinase activity, carries latent transglycosylating activity that becomes prominent only after mutation. We could not detect any hydrolyzing activity on pullulan consistent with the claim that E. coli does not contain pullulanase (34). At present, the physiological role, if any, of the ␥-cyclodextrinase activity of MalZ is unclear.…”

1,4-alpha-Gluean Phosphorylase from Klebsiella pneumoniae Purification, Subunit Structure and Amino Acid Composition

“…The studies reported were performed with our strain of Aerobacter aerogenes 1009 I11 [l] which has been classified by Richard as Klebsiella pneumoniae, noncapsulated, biotype d [6,19]. This classification is confirmed by our own results.…”

“…Both organisms belong to the same taxonomic group of coliform bacteria, but K. pneumoniae, unlike E. coli, is found more often 011 plants than in the intestinal tract [5]. There are conflicting reports on the occurrence of pullulanase in 292 Klebsiella pneumoniae Phosphorylase: Purification and Structure E. coli strains [4,6,7] as well as on the properlies of E. coli phosphorylase [S, 91. In this paper we describe the purification and specify some properties of a 1,4-aglucan phosphorylase which is induced when K. pneumoniae is grown on maltose as carbon source.…”

The Metabolic Role of Debranching Enzymes

“…Our report of an inducible pullulanase activity in E. colistrain ML has recently been questioned (Dessein & Schwartz, 1974). Dessein & Schwartz (1974) found no significant pullulanase activity in a systematic investigation of 51 E. colistrains.…”

“…In conclusion, four groups of organisms may be delineated with respect to the complement of enzymes constituting the exogenous pathway of branched 1 +a-glucan catabolism. These four pathways are: (1) pullulanase-amylase-maltodextrin permease; (2) pullulanass-maltodextrin permease; (3) maltodextrin permease (Dessein & Schwartz, 1974) ; (4) isoamylasemaltodextrin permease.…”