Aminopeptidases (EC. 3.4.11) in alfalfa (Medicago sativa L.) leaves

Biagioni, Massimo; Alpi, Amedeo; Picciarelli, Piero

doi:10.1016/s0176-1617(11)80636-x

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…Similar to protease pH optima, this indicates a mismatch between the environmental pH of the extracellular enzyme and the enzyme pH optima that may be attributable to pH‐dependent mechanism of catalysis, which likely evolved first for intracellular functions. For example, pH optima have been reported for purified LAP (pH 8.0–9.0) (Nampoothiri et al., 2005; Sopanen & Mikola, 1975), GAP (pH 8.0–8.4) (Ito et al., 2003; Ma et al., 2004; Murao et al., 1985), and AAP (pH 7.5–8.5) (Biagioni et al., 1990; Sidorowicz et al., 1981) of fungal, plant, and animal species. It should be noted that aminopeptidase activity pH optima have been found to be substrate‐sensitive by up to 1 pH unit (Biagioni et al., 1990), meaning that the apparent pH optima could differ from our chromogenic substrate ( p NA‐based) assays if assayed using fluorogenic or natural (e.g., dipeptide) substrates.…”

Section: Discussionmentioning

confidence: 99%

“…For example, pH optima have been reported for purified LAP (pH 8.0-9.0) (Nampoothiri et al, 2005;Sopanen & Mikola, 1975), GAP (pH 8.0-8.4) (Ito et al, 2003;Ma et al, 2004;Murao et al, 1985), and AAP (pH 7.5-8.5) (Biagioni et al, 1990;Sidorowicz et al, 1981) of fungal, plant, and animal species. It should be noted that aminopeptidase activity pH optima have been found to be substrate-sensitive by up to 1 pH unit (Biagioni et al, 1990), meaning that the apparent pH optima could differ from our chromogenic substrate (pNA-based) assays if assayed using fluorogenic or natural (e.g., dipeptide) substrates. Aminopeptidase activity did not necessarily exhibit a unimodel "peak" that is generally observed for purified enzymes, which may reflect the mix of isozymes and immobilized versus soil solution phases measured in aggregate by soil enzyme assays Wade et al, 2021).…”

Section: Aminopeptidasesmentioning

confidence: 99%

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Examining activity–pH relationships of soil nitrogen hydrolytic enzymes

Daughtridge,

Margenot

2024

Soil Science Soc of Amer J

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Nitrogen (N) depolymerization and mineralization in soils are catalyzed by extracellular enzymes, notably proteolytic and chitinolytic enzymes. However, there is limited knowledge of pH optima of these N‐hydrolytic soil enzymes, potentially missing insights to soil pH effects on N cycling and requiring assumptions on pH optima in enzyme activity assays. We evaluated pH optima of five N‐hydrolytic enzymes (casein protease, leucine aminopeptidase, glycine aminopeptidase, alanine aminopeptidase, N‐acetyl‐β‐glucosaminidase) in soils under long‐term (145‐year) fertilization and crop rotation treatments, as well as a restored prairie, on an Aquic Argiudoll. We additionally tested the pH dependency of three types of non‐enzymatic interferences in order to assess the relative importance of controls in determining N‐hydrolytic enzyme activity pH optima. For all enzymes, pH–activity relationships varied by soil and exhibited secondary pH optima, though primary pH optima generally agreed with values reported for purified, non‐soil enzymes. Enzyme activity pH optima did not reflect soil pH, though soil pH ranged 6.2–7.4 across 145‐year treatments. Nonenzymatic interference was generally pH‐dependent and soil‐specific for protease and N‐acetyl‐β‐glucosaminidase. Though omitting controls for dissolved organic matter tended to have the largest effect on pH optima misestimation, controlling for all three sources of interference had appreciable effects on estimated pH optima values. This study provides a benchmark of empirically determined pH optima of multiple hydrolytic enzymes that catalyze soil N depolymerization. We demonstrate that soil N‐hydrolytic enzyme activities exhibit pH optima that generally vary most by enzyme type, and specifically between proteolytic versus chitinolytic enzymes. Because pH optima of these soil enzyme activities can vary among soils differing in management and land use, pH optima should be determined a priori.

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Section: Discussionmentioning

confidence: 99%

Section: Aminopeptidasesmentioning

confidence: 99%

Examining activity–pH relationships of soil nitrogen hydrolytic enzymes

Daughtridge,

Margenot

2024

Soil Science Soc of Amer J

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Determination of sugars and cyclitols isolated from various morphological parts of Medicago sativa L

Al-Suod

Rațiu

Ligor

et al. 2018

J of Separation Science

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Plant research interest has increased all over the world, and a large body of evidence has been collected to show the huge potential of medicinal plants in various disease treatments. Medicago sativa L., known as alfalfa, is a rich source of biologically active components and secondary metabolites and was frequently used from the ancient times both as fodder crop and as a traditional medicine in the treatment of various diseases. Cyclitols, naturally occurring in this plant, have a particular interest for us due to their significant anti-diabetic, antioxidant, anti-inflammatory, and anti-cancer properties. In the present study we revealed the isolation, the identification, and the quantification of some cyclitols and sugars extracted from different morphological parts of alfalfa plant. Soxhlet extraction and solid phase extraction were used as extraction and purification methods, while for the analyses derivatization followed by gas chromatography with mass spectrometry was involved. The obtained results showed significant differences in the quantities of cyclitols and sugars found in the investigated morphological parts, ranging between 0.02 and 13.86 mg/g of plant in case of cyclitols, and in the range of 0.09 and 40.09 mg/g of plant for sugars. However, roots have the richest part of cyclitols and sugars in contrast to the leaves.

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Partial Purification and Properties of Aminopeptidases in Cotyledons of Cancavalia lineata L.

Yoon,

Kwon

1993

Molecules and Cells

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Aminopeptidases (EC. 3.4.11) in alfalfa (Medicago sativa L.) leaves

Cited by 5 publications

References 19 publications

Examining activity–pH relationships of soil nitrogen hydrolytic enzymes

Examining activity–pH relationships of soil nitrogen hydrolytic enzymes

Determination of sugars and cyclitols isolated from various morphological parts of Medicago sativa L

Partial Purification and Properties of Aminopeptidases in Cotyledons of Cancavalia lineata L.

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