Chemical modification studies of the active centre of Candida albicans chitinase and its inhibition by allosamidin

Milewski, Sławomir; O'Donnell, Raymond W.; Gooday, Graham W.

doi:10.1099/00221287-138-12-2545

Cited by 32 publications

(21 citation statements)

References 19 publications

(18 reference statements)

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“…Especially for the shorter incubation times the MU-release will be mainly caused by the allosamidin-inhibitable endochitinase. Furthermore, Milewski et al also found evidence for the existence of an endochitinase in C. albicans, showing higher activity with MU-[G1cNAc]n substrates of higher n-values (14). The third alter-native mentioned, in which a [ G1cNAc ] 2 unit was released from MU-[ G1cNAc ] 3 in the first step, would mean that an exochitinase-like enzyme initiated the degradation.…”

Section: Discussionmentioning

confidence: 99%

“…For MU-[ G1cNAc ] 2 the calculated specific activity increased by a factor of 7 and for MU-[ G1cNAc ] 3 the factor was only 3. It was already known that C. albicans contained various enzymes capable of hydrolyzing chitin or artificial substrates with one or more G1cNAc residues linked to either MU or nitrophenyl groups (4,9,14,20). According to the nomenclature proposed by Robbins et al (19) and Tronsmo and Harman (22) the following enzymes have been described in CC albicans: endochitinase, ex.ochitinase (chitobiosidase), non-reducing end chitobiase and jS-N-acetylhexosaminidase.…”

Section: Discussionmentioning

confidence: 99%

“…[G1cNAc]4 substrate was much higher than towards the corresponding substrates MU-[ G1cNAc ] 3 and MU-[ G1cNAc ] 2, an endochitinase character was proposed (14). We recently described the existence of a chitinase present in human serum (17).…”

mentioning

confidence: 99%

“…It is a dimeric derivative of the G1cNAc analogue N-acetylallosamine. The chitinase enzyme is inactive towards MU-[G1cNAc],, so it is apparently different from jS-N-acetylhexosaminidase (14). Since its activity towards the MU-…”

mentioning

confidence: 99%

“…In Candida albicans the presence of both chitinase (5,6,14) and chitobiase activities (20) has been described. Also mutants of these organism are known that are defective in chitobiase (9).…”

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confidence: 99%

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Discrimination between chitinase and chitobiase activities in Candida albicans.

Overdijk¹,

Steijn²

1995

J. Gen. Appl. Microbiol.

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Measurement of chitinase activity in crude homogenates of Candida albicans with the artificial substrates 4-methylumbelliferyl /3-D-N,N',N"-triacetylchitotrioside and 4-methylumbelliferyl/3-D-N,N'-diacetylchitobioside (MU-[G1cNAc]3,2) showed that both chitobiase and chitinase were involved in the liberation of the fluorophore methylumbelliferone (MU). The substrate MU-[G1cNAc]3 appeared to be digested by means of two separate mechanisms, resulting in a lag-phase in the time curve of the MU-release, and thus making this release non-linear with time. The first mechanism is the action of an endochitinase that released MU in one step; this reaction could be inhibited by allosamidin. The second probable mechanism involves the digestion of the substrate by the stepwise release of the outer two G1cNAc residues by a chitobiase, followed either by a third chitobiase-catalyzed release of the final G1cNAc or by the action of a,(3-N-acetylhexosaminidase, that is also present in C. albicans. Hydrolysis of the substrate MU-[ G1cNAc ] 2 was not inhibited by allosamidin, suggesting that the two G1cNAc residues in this substrate are probably released in two steps, either by the action of chitobiase alone, or by the successive action of chitobiase (step 1) and /3-N-acetylhexosaminidase (step 2). Our results show that the activities of the individual enzymes involved in chitin degradation cannot be determined on the basis of MU release in unfractionated homogenates of C. albicans.The literature on chitinases has been reviewed recently by Flach et al. (7).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Discrimination between chitinase and chitobiase activities in Candida albicans.

Overdijk¹,

Steijn²

1995

J. Gen. Appl. Microbiol.

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Inhibition of chitinolytic enzymes from Streptomyces griseus (bacteria), Artemia salina (crustacea), and a cell line from Chironomus tentans (insecta) by allosamidin and isoallosamidin

Spindler

Spindler-Barth

1994

Pestic. Sci.

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The influence of allosamidin and its diastereoisomer isoallosamidin on chitinase activity from an insect cell line of Chironomus tentans, the crustacean Artemia salina and the bacterium Streptomyces griseus was studied. The rank order of susceptibility of chitinase activity to both inhibitors was found to be: insects »crustaceans« fungi, although isoallosamidin is about 600‐fold (insect) or 400‐fold (crustacea) less active than allosamidin and does not inhibit chitinase from Streptomyces at all. The complete and exclusive inhibition of N‐acetyl‐β‐D‐glucosaminidase by an acetylgluconolactone‐derivative and chitinase activity by allosamidin indicates that both enzymes can be determined separately in crude extracts, (containing both enzymes), with the substrates 4‐methylumbelliferyl‐N‐acetylglucosaminide or 4‐methylumbelliferyl‐chitoriose, respectively.

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Inhibitors of chitinases

Spindler-Barth²

1999

Chitin and Chitinases

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Chemical modification studies of the active centre of Candida albicans chitinase and its inhibition by allosamidin

Cited by 32 publications

References 19 publications

Discrimination between chitinase and chitobiase activities in Candida albicans.

Discrimination between chitinase and chitobiase activities in Candida albicans.

Inhibition of chitinolytic enzymes from Streptomyces griseus (bacteria), Artemia salina (crustacea), and a cell line from Chironomus tentans (insecta) by allosamidin and isoallosamidin

Inhibitors of chitinases

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