Dephosphorylation of glycogen synthase in rat heart extracts by E. coli alkaline phosphatase

Regulation of the dephosphorylation of glycogen synthase in extracts from rat heart has been studied by adding exogenous phosphatase to the extract. These experiments were possible only because the endogenous protein phosphatase activity of the extract could be inhibited by KF under conditions where alkaline phosphatase activity was not. The concentration of substrate (glycogen synthase from the heart extract) and catalyst (purified E. coli alkaline phosphatase) could be varied independently, by adding known amounts of alkaline phosphatase to the KF-containing heart extracts. Alkaline phosphatase could completely dephosphorylate glycogen synthase while phosphorylase was unchanged. The rate of dephosphorylation was proportional to both the concentration of alkaline phosphatase added to the tissue extract and the amount of glycogen synthase in the extract. The Km for glycogen synthase was close to the concentration found in heart tissue. The Km and the maximum rate of dephosphorylation were both dependent on the phosphorylation state of the glycogen synthase. Less phosphorylated enzyme forms were dephosphorylated faster. These results indicate the necessity for precise control of many variables in studying the rate of glycogen synthase dephosphorylation. Alkaline phosphatase-catalyzed dephosphorylation could be inhibited by physiological concentrations of glycogen. Glycogen synthase dephosphorylation in extracts from fasted-refed rats was less sensitive to glycogen inhibition than in extracts from normal animals. The phosphorylation state of the glycogen synthase in these animals was assessed by kinetic studies to show that differences in phosphorylation state probably could not account for the observations. Fasting led to a decreased rate of dephosphorylation of glycogen synthase due to both an apparent change in kinetic properties of glycogen synthase as a substrate for alkaline phosphatase, and an increased inhibitory effect of glycogen. Stable modifications of glycogen synthase caused by altered nutritional states in the animals are thought to produce these effects.     

Dephosphorylation of glycogen synthase in rat heart extracts by E. coli alkaline phosphatase

Summary Regulation of the dephosphorylation of glycogen synthase in extracts from rat heart has been studied by adding exogenous phosphatase to the extract. These experiments were possible only because the endogenous protein phosphatase activity of the extract could be inhibited by KF under conditions where alkaline phosphatase activity was not. The concentration of substrate (glycogen synthase from the heart extract) and catalyst (purified E. coli alkaline phosphatase) could be varied independently, by adding known amounts of alkaline phosphatase to the KF-containing heart extracts. Alkaline phosphatase could completely dephosphorylate glycogen synthase while phosphorylase was unchanged. The rate of dephosphorylation was proportional to both the concentration of alkaline phosphatase added to the tissue extract and the amount of glycogen synthase in the extract. The K_m for glycogen synthase was close to the concentration found in heart tissue. The K_m and the maximum rate of dephosphorylation were both dependent on the phosphorylation state of the glycogen synthase. Less phosphorylated enzyme forms were dephosphorylated faster. These results indicate the necessity for precise control of many variables in studying the rate of glycogen synthase dephosphorylation.Alkaline phosphatase-catalyzed dephosphorylation could be inhibited by physiological concentrations of glycogen. Glycogen synthase dephosphorylation in extracts from fasted-refed rats was less sensitive to glycogen inhibition than in extracts from normal animals. The phosphorylation state of the glycogen synthase in these animals was assessed by kinetic studies to show that differences in phosphorylation state probably could not account for the observations. Fasting led to a decreased rate of dephosphorylation of glycogen synthase due to both an apparent change in kinetic properties of glycogen synthase as a substrate for alkaline phosphatase, and an increased inhibitory effect of glycogen. Stable modifications of glycogen synthase caused by altered nutritional states in the animals are thought to produce these effects.%GSI represents the percentage of glycogen synthase activity that is active without glucose 6-P.     

Storage and absorption in the digestive system of carnivorous and herbivorous prickleback fishes (Teleostei: Stichaeidae): ontogenetic, dietary, and phylogenetic effects

The effects of ontogeny, diet, and phylogeny on glycogen storage levels and esterase and alkaline phosphatase activities in four related prickleback fishes were determined in situ using quantitative histochemistry. Of these species, Cebidichthys violaceus and Xiphister mucosus shift from carnivory to herbivory at approximately 45 mm standard length (SL), whereas Xiphister atropurpureus and Anoplarchus purpurescens remain carnivores. Comparisons between small (30-40 mm SL) and larger (60-75 mm SL) wild-caught juveniles showed that glycogen storage levels and alkaline phosphatase activity were unchanged with ontogeny. Comparisons between the larger wild-caught juveniles and juveniles of the same size that had been raised on a high-protein animal diet revealed that glycogen storage level and alkaline phosphatase activity increased in all species in response to this diet. Esterase activity also increased in response to the high-protein animal diet in all four species but increased with ontogeny only in C. violaceus, X. mucosus, and X. atropurpureus, in the xiphisterine clade, and not in A. purpurescens, in the adjacent alectriine clade. Xiphister mucosus and X. atropurpureus showed indistinguishable responses in esterase activity to ontogeny and diet despite their divergent natural diets. Overall, glycogen storage level and alkaline phosphatase activity responded primarily to diet, whereas esterase activity was also influenced by ontogeny and phylogeny and differed between intestinal regions among the species.     

Cytochemical studies of rat liver glycogen and alkaline phosphatase under the effect of hepatocarcinogens.

Cytochemical changes of glycogen and alkaline phosphatase were studied under sequential effect of p-dimethylaminoazobenzene (DAB) feeding and CCl4 injections. It has been found that in liver cells of experimental animals, the concentration of glycogen and the activity of alkaline phosphatase were decreased.     

Effect of starvation on tissue and serum gluconeogenic enzymes, alkaline phosphatase and tissue glycogen in the freshwater catfish, Heteropneustes fossilis (Bloch).

The influence of starvation has been studied on tissue and serum G-6Pase F-D-Pase and alkaline phosphatase activities and on the muscle and liver glycogen content of the freshwater catfish H. fossilis (Bloch). A marked increase in G-6Pase and F-D-Pase activities and a fall in the muscle and liver glycogen content recorded during 40 day starvation. The rise in gluconeogenic enzymes during starvation may be due to glucocorticoid stimulation. Alkaline phosphatase activity was found to decline markedly during starvation. The decline in enzyme activity is attributed to some factors like a fall in the rate of synthesis caused by lowered metabolic demands and to electrolyte imbalance caused by tissue overhydration. The fall in glycogen content may be related to the starved condition of the fish. Elevation in glycogen content and alkaline phosphatase activity and a fall in gluconeogenic enzymes were noted when feeding had been resumed.     

Dephosphorylation of phosphoproteins of human liver plasma membranes by endogenous and purified liver alkaline phosphatases

Purified alkaline phosphatase and plasma membranes from human liver were shown to dephosphorylate phosphohistones and plasma membrane phosphoproteins. The protein phosphatase activity of the liver plasma membranes was inhibited by levamisole, a specific inhibitor of alkaline phosphatase, and by phenyl phosphonate and orthovanadate, but was relatively insensitive to fluoride (50 mM). Endogenous membrane protein phosphatase activity was optimal at pH 8.0, compared to pH 7.8 for purified liver alkaline phosphatase. Plasma membranes also exhibited protein kinase activity using exogenous histone or endogenous membrane proteins (autophosphorylation) as substrates; this activity was cAMP-dependent. Autophosphorylation of plasma membrane proteins was apparently enhanced by phenyl phosphonate, levamisole, or orthovanadate. The dephosphorylation of phosphohistones by protein phosphatase 1 was not inhibited by levamisole but was inhibited by fluoride. Inhibition of endogenous protein phosphatase activity by orthovanadate during autophosphorylation of plasma membranes could be reversed by complexation of the inhibitor with (R)-(-)-epinephrine, and the dephosphorylation that followed was levamisole-sensitive. Neither plasma membranes nor purified liver alkaline phosphatase dephosphorylated glycogen phosphorylase a. These results suggest that the increased [32P]phosphate incorporation by endogenous protein kinases into the membrane proteins is due to inhibition of alkaline phosphatase and that the major protein phosphatase of these plasma membranes is alkaline phosphatase.     

Qualitative and quantitative histochemical changes in the caecum and liver of turkeys infected with Histomonas meleagridis.

Changes in the amount and distribution of acid and alkaline phosphatase, non-specific esterase, glycogen, lipid and acid mucopolysaccharide in the caecal wall and liver of turkey poults infected with Histomonas meleagridis have been studied histochemically. A microdensitometer was used to measure changes in activity and distribution of acid phosphatase and non-specific esterase in the caecal mucosa. During the course of the infection there is a marked reduction in activity and distribution of acid phosphatase and non-specific esterase but little change in the amounts and distribution of alkaline phosphatase, glycogen, lipid and acid mucopolysaccharide in the wall of the main part of the caecum. Similar, but smaller, changes occurred in the wall of the neck region of the caecum. In the liver most changes occurred in the immediate vicinity of the parasites. Initially, there was a reduction in the amount of glycogen in the parasitic lesions but later in the infection there was a marked loss of glycogen in all regions of the liver. Changes in the caecum are apparently brought about by the parasite prior to and after invasion of the caecal tissues; changes in the liver occur after it has been invaded.     

Comparison of the substrate specificities of protein phosphatases involved in the regulation of glycogen metabolism in rabbit skeletal muscle.

Muscle extracts were subjected to fractionation with ethanol, chromatography on DEAE-cellulose, precipitation with (NH4)2SO4 and gel filtration on Sephadex G-200. These fractions were assayed for protein phosphatase activities by using the following seven phosphoprotein substrates: phosphorylase a, glycogen synthase b1, glycogen synthase b2, phosphorylase kinase (phosphorylated in either the alpha-subunit or the beta-subunit), histone H1 and histone H2B. Three protein phosphatases with distinctive specificities were resolved by the final gel-filtration step and were termed I, II and III. Protein phosphatase-I, apparent mol.wt. 300000, was an active histone phosphatase, but it accounted for only 10-15% of the glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activities and 2-3% of the phosphorylase kinase phosphatase and phosphorylase phosphatase activity recovered from the Sephadex G-200 column. Protein phosphatase-II, apparent mol.wt. 170000, possessed histone phosphatase activity similar to that of protein phosphatase-I. It possessed more than 95% of the activity towards the alpha-subunit of phosphorylase kinase that was recovered from Sephadex G-200. It accounted for 10-15% of the glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activity, but less than 5% of the activity against the beta-subunit of phosphorylase kinase and 1-2% of the phosphorylase phosphatase activity recovered from Sephadex G-200. Protein phosphatase-III was the most active histone phosphatase. It possessed 95% of the phosphorylase phosphatase and beta-phosphorylase kinase phosphatase activities, and 75% of the glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activities recovered from Sephadex G-200. It accounted for less than 5% of the alpha-phosphorylase kinase phosphatase activity. Protein phosphatase-III was sometimes eluted from Sephadex-G-200 as a species of apparent mol.wt. 75000(termed IIIA), sometimes as a species of mol.wt. 46000(termed IIIB) and sometimes as a mixture of both components. The substrate specificities of protein phosphatases-IIA and -IIB were identical. These findings, taken with the observation that phosphorylase phosphatase, beta-phosphorylase kinase phosphatase, glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activities co-purified up to the Sephadex G-200 step, suggest that a single protein phosphatase (protein phosphatase-III) catalyses each of the dephosphorylation reactions that inhibit glycogenolysis or stimulate glycogen synthesis. This contention is further supported by results presented in the following paper [Cohen, P., Nimmo, G.A. & Antoniw, J.F. (1977) Biochem. J. 1628 435-444] which describes a heat-stable protein that is a specific inhibitor of protein phosphatase-III.     

Role of corpora-allata and brain of adult female Lohita grandis gray

Removal of the corpora allata from the emerging female adults of L. grandis caused a rapid and significant increase in the contents of total carbohydrate, glycogen, total lipids, cholesterol, total proteins and RNA in the fat body, and a significant drop in the contents of trehalose free fatty acids (FFA), phospholipids, free amino acids (FAA) and also in the activity of acid and alkaline phosphatase, glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and exterase in the fat body, in comparison with the sham-operated controls. Treatment with juvenile hormone analogue (JHa) of the allatectomized insects significantly reverses the effects produced by allatectomy (P less than or equal to 0.01). Similarly, removal of the brain produced similar responses in the fat-body but with some exceptions such as the decrease of total protein and RNA and increase significant of FAA as compared to the sham-operated controls. Simultaneous removal of corpora-allata and brain produces a rapid increase in the contents of total carbohydrate, glycogen, total lipid, cholesterol, FAA and the activity of acid phosphatase in comparison with all other treatments performed in this study, while the contents of trehalose, phospholipid, FFA, total protein, RNA and the activity of GOT, GPT, general esterase and alkaline phosphatase in the fat-body decreased compared to all other treatments. The results obtained are discussed in relation to the neuro-endocrine control of metabolism in insects.     

Permethrin- and malathion-induced macromolecular abnormalities in adult Tribolium castaneum (herbst)

In Tribolium castaneum adults, sublethal doses of 1 and 2 ppm permethrin and 300 ppm malathion led to significant changes in amylase, trehalase, acid phosphatase, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and isocitrate dehydrogenase activities. Malathion at 150 ppm did not affect phosphatases and lactate dehydrogenase. Both malathion and permethrin significantly increased cholinesterase activity. Mixing of the two insecticides resulted in antagonistic action with reference to various enzymatic activities. Glucose and glycogen contents were at first mobilized for energy supply under insecticidal stress conditions followed by lipid and cholesterol. Soluble protein, total protein, free amino acids, and urea contents remained unaltered under all experimental conditions.     

Interrelationship of carbohydrate metabolism and alkaline phosphatase synthesis in Bacillus licheniformis 749/c.

Membrane-bound alkaline phosphatase of Bacillus licheniformis 749/c is derepressed by glucose in complex and chemically defined media. In the presence of lactate, pyruvate, or succinate the synthesis is repressed. The lactate repression neither affects total protein synthesis nor inhibits penicillinase synthesis. Thus, carbon sources specifically influence alkaline phosphatase synthesis. Although variations in the inorganic phosphate content of the growth media directly affect alkaline phosphatase synthesis, the intracellular inorganic and total phosphate pools appear to be unrelated to its repression or derepression. During lactate repression there is preferential incorporation of lactate molecules into glycogen, whereas no such incorporation could be detected from glucose. Net glycogen synthesis remains the same in glucose- or lactate-grown cells. It is postulated that, in phosphate-deficient growth medium, gluconeogenic metabolism regulates alkaline phosphatase synthesis.     

Status of phosphatase activities in the liver and kidney of rats treated with isosaline leaf and stem-bark extracts of Harungana madagascariensis (L)

The activities of phosphatases and other biochemical parameters were examined in rats treated with isosaline leaf and stem-bark extracts of Harungana madagascariensis (L). Results show that both the leaf and stem-bark extracts significantly increased the activities of serum and liver alkaline phosphatase, liver acid phosphatase, liver and kidney glucose-6-phosphatase, fructose-1,6-diphosphatase and glycogen in the treated rats. While the stem-bark extract significantly elevated the activities of fructose-1,6-diphosphatase and glycogen in the kidney, these biochemical parameters were not affected by treatment with the leaf extract. The activity of serum acid phosphatase was unaffected by the two extracts. The results obtained clearly show that these extracts caused a marked increase in gluconeogenesis in the liver and kidney of the treated rats. While the stem-bark extract increased gluconeogenesis in both liver and kidney, the leaf extract caused an increase in gluconeogenesis only in the liver. The increased serum alkaline phosphatase activity caused by these extracts may, aside from having other tissues contributing to it, be due to damage caused by these extracts to the hepatocytes. The extent of pathological changes as well as the implications of these findings to folklore medicine requires further investigation.     

The protein phosphatases involved in cellular regulation. Evidence that dephosphorylation of glycogen phosphorylase and glycogen synthase in the glycogen and microsomal fractions of rat liver are catalysed by the same enzyme: protein phosphatase-1

Glycogen synthase (labelled in sites-3) and glycogen phosphorylase from rabbit skeletal muscle were used as substrates to investigate the nature of the protein phosphatases that act on these proteins in the glycogen and microsomal fractions of rat liver. Under the assay conditions employed, glycogen synthase phosphatase and phosphorylase phosphatase activities in both subcellular fractions could be inhibited 80-90% by inhibitor-1 or inhibitor-2, and the concentrations required for half-maximal inhibition were similar. Glycogen synthase phosphatase and phosphorylase phosphatase activities coeluted from Sephadex G-100 as broad peaks, stretching from the void volume to an apparent molecular mass of about 50 kDa. Incubation with trypsin decreased the apparent molecular mass of both activities to about 35 kDa, and decreased their I50 for inhibitors-1 and -2 in an identical manner. After tryptic digestion, the I50 values for inhibitors-1 and -2 were very similar to those of the catalytic subunit of protein phosphatase-1 from rabbit skeletal muscle. The glycogen and microsomal fractions of rat liver dephosphorylated the beta-subunit of phosphorylase kinase much faster than the alpha-subunit and dephosphorylation of the beta-subunit was prevented by the same concentrations of inhibitor-1 and inhibitor-2 that were required to inhibit the dephosphorylation of phosphorylase. The same experiments performed with the glycogen plus microsomal fraction from rabbit skeletal muscle revealed that the properties of glycogen synthase phosphatase and phosphorylase phosphatase were very similar to the corresponding activities in the hepatic glycogen fraction, except that the two activities coeluted as sharp peaks near the void volume of Sephadex G-100 (before tryptic digestion). Tryptic digestion of the hepatic glycogen and microsomal fractions increased phosphorylase phosphatase about threefold, but decreased glycogen synthase phosphatase activity. Similar results were obtained with the glycogen plus microsomal fraction from rabbit skeletal muscle or the glycogen-bound form of protein phosphatase-1 purified to homogeneity from the same tissue. Therefore the divergent effects of trypsin on glycogen synthase phosphatase and phosphorylase phosphatase activities are an intrinsic property of protein phosphatase-1. It is concluded that the major protein phosphatase in both the glycogen and microsomal fractions of rat liver is a form of protein phosphatase-1, and that this enzyme accounts for virtually all the glycogen synthase phosphatase and phosphorylase phosphatase activity associated with these subcellular fractions.     

Phosphate binding in the active site of alkaline phosphatase and the interactions of 2-nitrosoacetophenone with alkaline phosphatase-induced small structural changes

To monitor structural changes during the binding of Pi to the active site of mammalian alkaline phosphatase in water medium, reaction-induced infrared spectroscopy was used. The interaction of Pi with alkaline phosphatase was triggered by a photorelease of ATP from the inactive P(3)-[1-(2-nitrophenyl)]ethyl ester of ATP. After photorelease, ATP was sequentially hydrolyzed by alkaline phosphatase giving rise to adenosine and three Pi. Although a phosphodiesterase activity was detected prior the photorelease of ATP, it was possible to monitor the structural effects induced by Pi binding to alkaline phosphatase. Interactions of Pi with alkaline phosphatase were evidenced by weak infrared changes around 1631 and at 1639 cm(-1), suggesting a small distortion of peptide carbonyl backbone. This result indicates that the motion required for the formation of the enzyme-phosphate complex is minimal on the part of alkaline phosphatase, consistent with alkaline phosphatase being an almost perfect enzyme. Photoproduct 2-nitrosoacetophenone may bind to alkaline phosphatase in a site other than the active site of bovine intestinal alkaline phosphatase and than the uncompetitive binding site of L-Phe in bovine intestinal alkaline phosphatase, affecting one-two amino acid residues.     

Evidence for the coordinate control of activity of liver glycogen synthase and phosphorylase by a single protein phosphatase.

Homogeneous rabbit liver phosphorylase phosphatase (Brandt, H., Capulong, Z. L., and Lee, E. Y. C. (1975) J. Biol. Chem. 250, 8038-8044) also dephosphorylates glycogen synthase b. During purification, phosphorylase phosphatase and glycogen synthase phosphatase co-purified with a constant ratio of activities. The two activities co-migrated on disc gel electrophoresis. Both substrates competed with each other for the phosphatase, and both phosphatase activities were inhibited by lysine ethyl ester. It is concluded that liver phosphorylase phosphatase and glycogen synthase phosphatase have a common identity and that coordinate regulation of the phosphatase-catalyzed activation of glycogen synthase and inactivation of phosphorylase occurs in vivo. This provides a parallel and opposing mechanism to that mediated by adenosine 3':5'-monophosphate-dependent protein kinase, which coordinately inactivates glycogen synthase and, via phosphorylase kinase, activates phosphorylase. Maximal glycogen synthase phosphatase activity was observed near neutrality. Mg2+ and glucose-6-P activated the glycogen synthase phosphatase reaction and this activation was pH-dependent. The Km for glycogen synthase b was 0.12 muM.     

Phosphoprotein-phosphatase activity associated with human placental alkaline phosphatase.

Human placental alkaline phosphatase, a marker protein for some nontrophoblastic neoplasms, was found to have phosphoprotein phosphatase activity. This was demonstrated by the dephosphorylation of ³²P-labeled histones, protamine, glycogen synthetase, casein, and phosvitin at various pH values. Unlike the general phosphoprotein phosphatase, the placental alkaline phosphatase does not have phosphorylase $\text{a}$ phosphatase activity.     

Isolation of the alkaline phosphatase from the intestinal contents of common seal by immobilized monoclonal antibodies]

It is shown that monoclonal antibodies against the alkaline phosphatase of the Greenland seal interact with the alkaline phosphatase of the bowels contents of adult common seal (Phoca vitulina larga). The purified antibodies were covalently bound with BrCn-activated sepharose 4B and used as an immunosorbent for purification of the alkaline phosphatase of the bowels contents. The specific activity of the purified is equal to 7300 units per 1 mg of protein.     

Fine structural localization of alkaline phosphatase in the granular pneumonocytes of hamster lung.

The fine structural localization of nonspecific alkaline phosphatase was studied in the granular pneumonocytes (type II alveolar epithelial cells) of hamster lung by incubating sections of glutaraldehyde-fixed tissues in a medium containing lead ions and sodium beta-glycerophosphate or alpha-naphthyl acid phosphate. The specificity of the reaction was tested by exposing the sections to inhibitors of alkaline phosphatase. The results showed that alkaline phosphatase activity was present in the inclusion bodies of granular pneumonocytes. The enzyme reaction was strong in the membrane lining the inclusion bodies and a weaker reaction was generally detectable in the inclusion contents. Although only a proportion of the inclusion bodies showed enzyme activity, there was no obvious correlation between the reactivity of the inclusions and their intracellular position or size. The other organelles were unreactive. The finding of alkaline phosphatase activity within the inclusion bodies of granular pneumonocytes is an enigma as these organelles are generally considered to be lyosomes.     

Biochemical effects of sublethal doses of cypermethrin on the sixth-instar larvae of Tribolium castaneum (Herbst.)

Effects of sublethal doses ie, 2, 4, 10, and 20 ppm of cypermethrin, were studied on the sixth-instar larvae of Tribolium castaneum (Herbst.). Of all the biochemical parameters tested, the free amino acids and cholesterol content and the activity of amylase were found to be the most sensitive components. Glutamate pyruvate transaminase activity was elevated at all doses except 2 ppm. The activities of alkaline phosphatase and glutamate oxaloacetate transaminase and glucose content were raised significantly at doses of 10 and 20 ppm. Acid phosphatase activity and the soluble protein content increased at a dose of 20 ppm. Total lipid and triglycerides, however, decreased significantly at this sublethal dose. Other biochemical parameters, such as cholinesterase and lactate dehydrogenase activities and the total protein, urea, glycogen, DNA, and RNA contents, were not significantly affected by exposure to different doses of cypermethrin.     

桃小食心虫幼虫越冬前后对几种杀虫剂敏感性的差异

用药液浸渍法测定了桃小食心虫幼虫越冬前和越冬后对三唑磷、辛硫磷、马拉硫磷、毒死蜱、高效氯氟氰菊酯和阿维菌素等杀虫剂的敏感性差异.结果表明:越冬后幼虫对上述药剂的敏感性分别是越冬前幼虫的34.50、16.71、3.89、3.28、5.90和2.73倍.幼虫越冬后体内能源物质蛋白质、糖元和脂肪含量分别比越冬前降低17.10%、41.76%和30.08%;羧酸酯酶、酸性磷酸酯酶、碱性磷酸酯酶及谷胱甘肽-S-转移酶的活力分别比越冬前降低62.36%、53.47%、76.19%和80.60%;超氧化物歧化酶、过氧化氢酶、过氧化物酶等保护酶活力比越冬前分别降低18.77%、14.16%和64.02%;而幼虫体内多种农药的靶标酶乙酰胆碱酯酶活力的变化则相反,该酶在越冬后幼虫体内的活力是越冬前的1.41倍.表明越冬后幼虫对药剂敏感性的提高与体内能源物质含量、代谢酶、保护酶和靶标酶的活力变化有关.