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PubMed1979

Protein quality in cereals and pulses. 3. Bioassays with rats and chickens on sorghum (Sorghum vulgare Pers.), barley and field beans (Vicia faba L.). Influence of polyethylene glycol on digestibility on the protein in high-tannin grain.

1. Two preceding papers in this series describe the application of microbiological and other in vitro tests in the evaluation of sorghum (Sorghum vulgare Pers.), field beans (Vicia faba L.) and barley, and in assessing the influence of polyethylene glycol (PEG 4000) on the nutritional availability of the methionine. The present paper gives for comparison the results of bioassays on some of the same test samples. Net protein utilization (NPU) in rats was measured by the nitrogen balance method, and N digestibility in chickens by the ileal analysis procedure. 2. In rat tests on sorghum, N in grain of high-tannin varieties was poorly digested. Supplementation of the test diets with 0.1 g PEG 4000/g protein gave a large improvemnet, which was partly offset by an apparent decrease in biological value (BV). With chickens N digestibility was even lower, and was similarly improved with PEG 4000. Treatment of high-tannin grain with ammonia solution was also effective in improving N digestibility. 3. With low-tannin sorghum the amino acid digestibilities were uniformly high and were not affected by addition of PEG to the test diet. With high-tannin sorghums they were low and less uniform, and were much improved by PEG 4000. 4. With field beans, the influence of the seed-coat tannin on protein utilization was much less pronounced than with sorghum. In chickens there was a significant effect (P less than 0.05) of PEG 4000 on N idgestibility in a high-tannin variety. With rats the effect was smaller and not significant. 5. In four samples of barley. N digestibility was high (0.87--0.96) and was not further improved by PEG 4000. The BV of a high-lysine cultivar proved marginally inferior to that of a normal variety. Possible reasons for this are discussed. 6. Over all, the results were closely consistent with those from microbiological tests with Streptococcus zymogenes.

Animals↗
PubMed1986

Tannin analysis of food products.

Phenolic substances occur primarily in fruits and vegetables and in the seeds of certain pigmented cultivars of sorghum, millets, and legumes. One of the major difficulties encountered in polyphenol research is the lack of a standard quantitative method for the analysis of phenolics that would be suitable for a wide range of seeds, forage crops, and food products and under a variety of experimental conditions. Some methods measure "total phenol", which may not be a true index of the nutritional quality of foods and thus does not distinguish polyphenols of nutritional concern from other low-molecular-weight phenols that also occur naturally in these products. Tannic acid (a hydrolyzable gallotannin) is commonly used as a "reference standard", but this may be a questionable practice since its biological properties differ from those of tannins of flavonoid origin. Polyphenols of cereals and legumes are predominantly of the latter type. Also, commercially available tannic acid has been shown to be a mixture of four phenolic compounds, the relative proportions of which vary with the samples. Thus, the choice of a suitable standard for tannin analysis is also important. The quantitative extraction of the condensed tannins from plant tissue is always difficult, since it may be complexed to a carbohydrate or protein matrix which could be quite insoluble due to a high degree of polymerization. The literature on tannin methodology is diverse and at times conflicting. Currently available methods for tannin analysis range from simple colorimetric, UV spectrophotometric, chromatographic, and enzymic to more sophisticated and expensive nuclear magnetic resonance (NMR) techniques. None of these methods of analyses is completely satisfactory nor can it be applied to different food products with the same degree of success. This review covers physical and chemical methods for tannin analysis of different food products, the problems in analysis and interpretation of data, and future research needs in this area.

Benzaldehydes↗
PubMed2006

Pre-ozonation of commercial textile tannins: effects on biodegradability and toxicity.

The effect of ozonation on the biodegradability and acute toxicity of two frequently used textile dye assisting chemicals, namely natural tannin (NT) having an initial chemical oxygen demand (COD0) of 1195 mg L-1; initial total organic carbon (TOC0) of 342 mg L-1; initial 5th-day biochemical oxygen demand (BOD5,0) of 86 mg L-1; initial ultraviolet absorbance at 280 nm wavelength (UV280,0) of 32.2 cm-1; initial ultraviolet absorbance at 254 nm wavelength (UV254,0) of 19.35 cm-1 and synthetic tannin (ST); with a COD0 of 465 mg L-1; TOC0 of 155 mg L-1; BOD5,0 of 6 mg L-1; UV280,0 of 11.78 cm-1; UV254,0 of 13.74 cm-1 was investigated. Synthetic wastewater bearing these tannin formulations was individually prepared and subjected to ozonation at varying doses (500 and 1000 mg h-1), and pHs (3.5 and 7.0) to elucidate the effect of ozone dose and pH on oxidation efficiency. Changes in the environmental sum parameters chemical oxygen demand (COD), total organic carbon (TOC), 5th-day biochemical oxygen demand (BOD5), ultraviolet absorbance at 280 nm wavelength (UV280) and ultraviolet absorbance at 254 nm wavelength (UV254), the latter two representing the aromaticity and double bonds of the studied textile tannins, respectively, were monitored during the course of ozonation. In the second part of the study, the biodegradability and acute toxicity of the raw and pre-ozonated textile tannins were evaluated in terms of the BOD5 parameter and an activated sludge inhibition test, respectively. Results indicated no significant changes in acute toxicity for NT, whereas the inhibitory effect of ST could be completely eliminated after 40 min ozonation at a rate of 1000 mg h-1 (i.e., at a specific ozone dose of 1.4 mg (O)3 (mg COD0)-1 and a pH of 3.5. In conclusion, pre-ozonation appeared to be potential pretreatment option to achieve complete detoxification and a fair biodegradability improvement of the otherwise refractory synthetic tannin.

Biodegradation, Environmental↗
PubMed1994

Dietary grape seed tannins affect lipoproteins, lipoprotein lipases and tissue lipids in rats fed hypercholesterolemic diets.

The effects of monomeric and polymeric grape seed tannins on rat plasma lipoproteins, lipoprotein lipase, hepatic lipase and aortic and hepatic lipid concentration were studied. Male Sprague-Dawley rats received either a normal diet (with no added cholesterol and no tannins), a control diet (hypercholesterolemic diet) or hypercholesterolemic diets supplemented with 2% tannin monomers or 2% polymers 3 or 9 wk. Plasma total cholesterol, triacylglycerol, LDL cholesterol and VLDL concentrations were significantly higher and the HDL cholesterol concentration lower in controls and in rats fed the diet supplemented with monomers compared with rats fed polymeric tannins at both time points. Lipoprotein lipase and hepatic lipase activities were significantly higher in control and in monomer-fed groups than in the polymer-fed group. Hepatic and aortic cholesterol and triacylglycerol concentrations were significantly higher in control rats and those fed monomers than in the polymer-fed group. Moreover, plasma HDL cholesterol and hepatic lipase activity were closely associated with low aortic cholesterol and triacylglycerol in rats fed polymeric tannins. These rats also exhibited greater fecal excretion of cholesterol and especially bile acids than the control or monomer-fed groups. Thus dietary grape seed tannins have a pronounced anti-hypercholesterolemic effect by enhancing reverse cholesterol transport and also by reducing intestinal cholesterol absorption and increasing bile acid excretion.

Animals↗
PubMed2003

Sn, a maize bHLH gene, modulates anthocyanin and condensed tannin pathways in Lotus corniculatus.

Anthocyanins and condensed tannins are major flavonoid end-products in higher plants. While the transactivation of anthocyanins by basic helix-loop-helix (bHLH) transcription factors is well documented, very little is known about the transregulation of the pathway to condensed tannins. The present study analyses the effect of over-expressing an Sn transgene in Lotus corniculatus, a model legume, with the aim of studying the regulation of anthocyanin and tannin end-products. Contrary to expectation, effects on anthocyanin accumulation were subtle and restricted to the leaf midrib, leaf base and petiole tissues. However, the accumulation of condensed tannin polymers was dramatically enhanced in the leaf blade and this increase was accompanied by a 50-fold increase in the number of tannin-containing cells in this tissue. A detailed analysis of selected lines indicated that this transactivational phenotype correlated with high steady-state transcript levels of the introduced transgene and the introduction of a single copy of the CaMV35S-Sn construct into these clonal genotypes. While the levels of condensed tannins in leaves were increased by up to 1% of the dry weight, other major secondary end-products (flavonols, lignins and inducible phytoalexins) were unaltered in transactivated lines. These results give an initial insight into the developmental and higher-order regulation of polyphenolic metabolism in Lotus and other higher plant species.

Anthocyanins↗
PubMed2001

Effect of hydrolysable and condensed tannins on growth, morphology and metabolism of Streptococcus gallolyticus (S. caprinus) and Streptococcus bovis.

Streptococcus gallolyticus (S. caprinus) was resistant in vitro to at least 7% (w/v) tannic acid and 4% (w/v) acacia condensed tannin, levels 10-fold greater than those tolerated by S. bovis. Growth of S. gallolyticus in liquid medium was characterized by a lag period which increased, and a growth rate which decreased, with increasing tannin concentration. S. gallolyticus was also more tolerant to the presence of simple phenolic acid monomers than was S. bovis, but the lag period was still concentration dependent. Gallate decarboxylase activity in S. gallolyticus was elevated in the presence of tannic acid or gallic acid but not with other phenolic acids. Scanning electron microscopic analysis showed that both the size and shape of S. gallolyticus and S. bovis changed in response to tannin but only S. gallolyticus was surrounded by an extracellular polysaccharide matrix which accumulated in a tannin-concentration-dependent fashion. Washing of the cells to remove extracellular polysaccharide increased the lag period of S. gallolyticus in the presence of 1% (w/v) tannic acid from 4 h to 6 h. In contrast, increasing extracellular polysaccharide synthesis in S. bovis did not increase its tolerance to tannic acid. These data demonstrate that S. gallolyticus has developed a number of mechanisms to reduce the potential effect of tannins on cell growth, and that these mechanisms provide the organism with a selective advantage over S. bovis when grown in the presence of tannins.

Carboxy-Lyases↗
PubMed1991

Selective inactivation of human neutrophil elastase by synthetic tannin.

Tannins of natural or synthetic origin are well-known adjuvants in topical anti-inflammatory therapy of skin diseases. In this study, the influence of synthetic tannin on neutrophil accumulation, enzyme release, and on the proinflammatory activity of neutrophil-derived enzymes was investigated. The results show that synthetic tannin (Tamol) specifically inhibits the neutrophil serine protease human leukocyte elastase (HLE) in an irreversible manner with a half-maximal inhibitory concentration (IC50) of 0.3 microgram/ml. Exogenous protein partially abolished the tannin-dependent HLE inhibition (IC50 of Tamol at 1% protein-concentration:1.0 microgram/ml). Synthetic tannin did not influence the activities of other neutrophil enzymes like Cathepsin G, beta-glucuronidase, and myeloperoxidase. The specificity of Tamol for HLE was further substantiated by the lack of inhibition of other serine proteases. Additionally, Tamol had no effect on f-met-leu-phe-induced neutrophil chemotaxis and did not alter enzyme degranulation of neutrophils in response to f-met-leu-phe and opsonized zymosan. We conclude from our results that the anti-inflammatory properties of synthetic tannin may at least in part be due to inactivation of the proinflammatory protease HLE.

Cell Degranulation↗
PubMed1990

Effect of alkali treatment on physiological activity of cotton condensed tannin.

Cotton dusts contain condensed tannins and endotoxins, which are suspected of contributing to the development of acute and chronic biological responses in some cotton textile mill workers. Condensed tannin extracted from cotton dust was coated on to cellulose powder, and the tannin coated powder was treated with an alkali solvent system previously developed to reduce the endotoxin content and pulmonary toxicity of cotton dust. Physiological activities of the dusts and powders were compared by assaying the production of the arachidonic acid metabolites prostaglandin F2 alpha (PGF2 alpha), thromboxane A2 (TxA2) (the precursor to thromboxane B2 (TxB2], leukotriene C4 (LTC4), and prostaglandin E2 (PGE2) by guinea pig pulmonary cells obtained by lung lavage. Cotton dust stimulated the pulmonary cells to produce a total of 29 pg metabolites per 10(6) cells. Production of metabolites by cells stimulated with tannin coated cellulose powder was reduced to 8.3 pg/10(6) cells. Alkali treatment of the tannin coated cellulose powder resulted in a further decrease in its ability to stimulate the cells, producing 3.5 pg metabolites per 10(6) cells. The ability of the dusts and powders to stimulate production of metabolites of arachidonic acid by pulmonary cells from guinea pigs was highly correlated with tannin content of the materials, but not with endotoxin content as measured by the Limulus amoebocyte lysate (LAL) assay.

Animals↗
PubMed1994

Effect of flavan-3-ol tannins purified from Camellia sinensis on lipid peroxidation of rat heart mitochondria.

We induced lipid peroxidation in rat heart mitochondria with FeSO4 and compared the inhibitory effect of various flavan-3-ol tannins on it. These tannins were purified from Chinese tea (Camellia sinensis). Oxygen consumption and malondialdehyde formation were used to quantitate the amount of lipid peroxidation. The free radical scavenger activity of tannins was then measured with a diphenyl-p-picrylhydrazyl method. These tannins significantly inhibited lipid peroxidation at micromolar concentration. Their potencies were higher than that of Trolox, a water soluble analogue of vitamin E. Since epicatechin-3-O-gallate, epigallocatechin-3-O-gallate and gallocatechin-3-O-gallate were more potent than other flavan-3-ol tannins in these assays, we considered that a galloyl group in 3-O-position increased the scavenger activity of flavan-3-ol tannins as well as their potency in inhibiting lipid peroxidation.

Animals↗
PubMed1989

Tannin induces endothelium-dependent contraction and relaxation of rabbit pulmonary artery.

The effects of tannin purified from cotton bracts were studied on pulmonary artery rings isolated from rabbit lungs. Tannin (2 to 50 micrograms/ml) caused concentration-dependent contractions of resting vessels, and maximal responses averaged 25% of the contraction induced by 10(-4) M exogenous norepinephrine. Tannin-induced contractions were blocked by removal of the endothelium and by pretreatment of intact tissues with either indomethacin or SQ 29,548, a thromboxane A2 receptor antagonist. In contrast, tissues contracted with 3 x 10(-7) M norepinephrine relaxed by 49 +/- 8% in response to 50 micrograms/ml tannin. Tannin-induced relaxations were unaltered by pretreatment of tissues with indomethacin but were significantly reduced by pretreatment with hemoglobin. We conclude that tannin causes the release of both smooth muscle contracting and relaxing factors from pulmonary artery endothelial cells. Thromboxane A2 is the contracting factor, whereas an endothelium-derived relaxing factor such as nitric oxide appears to be the primary relaxing factor that is released.

Animals↗
PubMed1986

Effects of endotoxin and tannin isolated from cotton bracts on the airway epithelium.

The effects of increasing concentrations of tannin isolated from cotton bracts and endotoxin prepared from Enterobacter agglomerans on the electrophysiologic and ion transport properties of the canine tracheal epithelium mounted in Ussing chambers were examined. Results were compared with those obtained using cotton bracts extract (CBE). Tannin concentrations in the isolated tannin and in the cotton bracts were analyzed spectrophotometrically. When added to the mucosal bathing solution, tannin produced a significant decrease in transepithelial potential difference and short-circuit current (lsc) with a maximal response at 25 microliter. The decrease in lsc was accounted for entirely by a decrease in net chloride secretion. The effects were reversible and specific for the mucosal bathing solution. In contrast to CBE, tannin had no effect on mannitol flux, suggesting no effect on the paracellular pathway. Endotoxin at a concentration of 10 micrograms/ml had no effect on the electrophysiologic properties of the canine trachea. We conclude that tannin in CBE is responsible for the decrease in lsc observed with aqueous extracts of CBE but is not responsible for the changes in the paracellular pathway. We also conclude that endotoxin alone has no effect on the airway epithelium.

Animals↗
PubMed1999

Inhibitory effects of tannins on the NADH dehydrogenase activity of bovine heart mitochondrial complex I.

NADH-quinone oxidoreductase is classified into two groups, NADH dehydrogenase-1 (NDH-1) and NADH dehydrogenase-2 (NDH-2). Animal mitochondrial complex I is an NDH-1 type enzyme. Previously, we isolated potent inhibitors from plants to both NDH-1 and NDH-2. We have now examined detailed inhibitory effects of three tannins (pentagalloylglucose, sanguiin H-11, and oolonghomobisflavan A) on NDH-1 using bovine heart mitochondrial complex I and a subcomplex flavoprotein (containing 3 subunits) derived from complex I. Although many specific inhibitors of NDH-1 (e.g. rotenone and piericidin A) have been reported, the reactive sites are at or near to, the ubiquinone-binding site. NADH-ubiquinone-1 oxidoreductase activity of complex I was inhibited by the three tannins, among which sanguiin H-11 was the most potent inhibitor. NADH-menadione oxidoreductase activity of complex I was susceptible to the three tannins, but completely resistant to rotenone. The inhibitory effects of tannins were all noncompetitive with respect to NADH, ubiquinone-1, and menadione. The NADH-menadione oxidoreductase of flavoprotein was also inhibited by the three tannins, but not by rotenone, which is consistent with the fact that flavoprotein does not contain a native ubiquinone-binding site. The study of the NADH reduced-minus-oxidized difference spectrum of flavoprotein under steady-state conditions indicated that the inhibitory sites of sanguiin H-11 and oolonghomobisflavan A exist between the NADH binding site and the FMN site, and that for pentagalloylglucose exists between FMN and an artificial electron acceptor-binding site. These results suggest that the tannins are potent inhibitors of NADH dehydrogenases, and that the inhibitory mechanisms are novel.

Animals↗
PubMedDate not supplied

Isolation and evaluation of tannin-degrading fungal strains from the Mexican desert.

Eleven fungal strains (4 Penicillium commune, 2 Aspergillus niger, 2 Aspergillus rugulosa, Aspergillus terricola, Aspergillus ornatus and Aspergillus fumigatus) were isolated, characterized morphologically and by their capacity to degrade tannins. Aspergillus niger Aa-20 was used as control strain. Several concentrations of hydrolysable tannin (tannic acid) were used as sole carbon source. All strains were able to degrade hydrolysable tannins. Aspergillus niger GH1 and PSH showed the highest tannin-degrading capacity (67 and 70%, respectively). Also, the fungal capacity to degrade condensed tannin (catechin) was tested. Aspergillus niger PSH and Penicillium commune EH2 degraded 79.33% and 76.35% of catechin. The results demonstrated the capacity of fungi to use hydrolysable and condensed tannins as carbon source.

Biodegradation, Environmental↗
PubMed1990

Comparative effects of dietary tannins in ducks, chicks, and rats.

Studies were conducted to compare the effects of feeding high-tannin sorghum (HTS)- and low-tannin sorghum (LTS)-based diets suboptimal in protein to ducks, chicks, and rats. In the first series of experiments, Savanna (HTS) depressed both growth and feed efficiency of chicks and rats when compared with animals fed RS-610 (LTS). In contrast, ducks fed Savanna-based diets exhibited greater weight gains, but poorer feed efficiency values than birds fed RS-610. In a second series of experiments, Pioneer 8333 (LTS) and DeKalb BR-64 (HTS) sorghum-soybean meal diets were fed to chicks, ducks, and rats. As compared with animals fed 8333, BR-64 depressed both growth and feed efficiency of chicks and rats, but did not significantly affect either parameter in ducks. The lack of effect of HTS on duck growth may have been due to the formation of tannin-protein complexes upon exposure of the ground grain to water. This theory was based on the following observations: 1) ducks consumed water immediately after eating to facilitate swallowing the dry-mash diet; 2) a large amount of feed was deposited on the bottom of each water trough and subsequently consumed; and 3) ground HTS, which had been soaked for 4 h, had virtually no assayable tannin after drying. However, despite the marked reduction in assayable tannin content of treated HTS versus HTS that was dried only, the former material still depressed growth and feed conversion of rats. Thus, the lack of a growth-depressing effect of sorghum tannins in ducks fed dry-mash diets is both unique and unexplained.

Analysis of Variance↗
PubMed2003

[Study on the kinetic fluorimetric determination of tannins in tea].

A simple and highly sensitive kinetic fluorimetric method is proposed for the determination of trace tannins, based on the activation of tannins on the oxidation of pyronine Y by hydrogen peroxide catalyzed by Cu(II) ion. The effects of some experimental conditions were investigated and discussed in detail. The fixed reaction time procedure was used to determine the fluorescence intensity of the system. The calibration curve of tannin was linear in the range of 0.06-0.96 mg.L-1, and the detection limit for tannin was 0.032 mg.L-1. The relative standard deviation for the measurement of 0.32 mg.L-1 tannin (n = 11) was 2.3%. The proposed method has been successfully applied to the determination of tannins in tea. The results obtained were compared with those provided by the Folin-Ciocalteu method.

Calibration↗
PubMed2003

Anaerobic treatment of natural tannin extracts in UASB reactors.

Tannin extracts are substances commonly used in leather production processes. Since most of the steps of tannery manufacturing processes are carried out in aqueous environments, the presence of these compounds in the wastewaters is important. The aim of this work is to study the feasibility of the anaerobic degradation of three natural tannin extracts in three Upflow Anaerobic Sludge Blanket (UASB) reactors, which were fed with increasing concentrations of two condensed (quebracho and wattle) and one hydrolysable tannin extract (chestnut). Concentrations of applied extracts were 100, 200, 400, 800 and 1,000 mg/l, and 5 g/l of glucose was used as cosubstrate. Reactors were operated during 210 days and their performance was evaluated from the values of total and soluble COD, total and intermediate alkalinity, volatile fatty acids, pH and UV absorption at 280 nm. COD removal efficiencies higher than 85% were achieved in all cases. However, tannin extract removal efficiencies (based on UV-280 nm absorption measurements) were significantly lower, around 20% for condensed extracts and 60% for the hydrolysable one, when the reactors operated with the highest tannin extract concentration. The operation of the reactors was stable, commonly with alkalinity ratios below 0.30. Mass balances carried out indicate that most of the COD removal efficiencies are due to the removal of the readily biodegradable organic matter (glucose), whereas the tannin extracts are hardly anaerobically biodegradable, especially condensed extracts (wattle and quebracho).

Animals↗
PubMed1988

Protein phosphorylation during tannin-mediated activation of human platelets.

Experiments to explore human platelet protein phosphorylation changes and 5-hydroxytryptamine (5-HT) secretion after challenge with cotton bract tannin were performed. Quantitative changes in sodium phosphate phosphorus 32 incorporation in two platelet proteins of 19 kilodaltons (kd) and 47 kd were assessed by measuring protein band densities on autoradiographs of dried polyacrylamide gels. Secretion of 5-HT was assessed by 14C-5-HT release. Results show that tannin causes increases in phosphorylation of discrete platelet proteins that begin in less than 2 seconds. These increases are maximal in 1 minute for the 47 kd protein and in 3 minutes for the 19 kd protein. Fifty percent of maximum response required less than 2 seconds for both of these proteins, and 50% of maximum 5-HT secretion required 48 seconds. Dose-response studies comparing 0 to 50 micrograms/ml tannin with 0 to 1 U/ml human alpha-thrombin showed that tannin caused 5-HT secretion and protein phosphorylation changes that were very similar to those induced by human alpha-thrombin. Fifty micrograms per milliliter of tannin caused increases in 19 kd protein phosphorylation and 47 kd protein phosphorylation to 312% +/- 34% (SEM) and 204% +/- 13% of control, respectively (n = 14). One unit per milliliter of thrombin induced changes of 350% +/- 40% and 221% +/- 17% of control in the 19 kd and 47 kd proteins, respectively. Release of 5-HT by tannin and thrombin was 61% +/- 3% and 69% +/- 3% of total cellular 5-HT, respectively. Indomethacin had little inhibitory effect on activation by these two different agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1995

Dietary effects of faba-bean (Vicia faba L.) tannins on the morphology and function of the small-intestinal mucosa of weaned pigs.

The objective of the present study was to evaluate effects of condensed tannins in faba beans (Vicia faba L.) on morphological and functional variables of the small-intestinal mucosa of piglets. In an experiment with young piglets (8-17 kg body weight), fed on either a control diet or a diet containing 200 g/kg of low- or high-tannin faba bean hulls (with < 0.10 and 3.3% catechin equivalents of condensed tannins respectively), morphological and functional characteristics of the jejunal mucosa were determined. Results of the study showed that the morphological variables of the mucosa of the three groups of piglets were similar. Also, no changes due to dietary tannins were observed in sucrase (EC3.2.1.48)-isomaltase (EC 3.2.1.10) activity in homogenates of mucosa plus submucosa. However, aminopeptidase (EC 3.4.11.2) activity in these homogenates in the proximal part of the small intestine of the animals of the group fed on the high-tannin diet was significantly lower than that in the animals fed on the control diet or the diet with low-tannin hulls (P < 0.05).

Aminopeptidases↗