[Chi-liang Kwei and an unfulfilled plan of establishing a modern psychiatric hospital in China]

Church General Hospital in Wuchang, China planned to establish a psychiatric hospital in 1930. Chi-liang Kwei, received his PhD at Johns Hopkins Medical School of America and was appointed to be in charge of the preparation. After working out a draft plan for the hospital, Dr. Kwei applied for the Henderson Research Scholarship on Mental Diseases. She planned to study under the guidance of Dr. D.K. Henderson in the Glasgow Mental Royal Hospital for a full year in preparation for the establishment of the hospital. By drawing on the correspondence files of Chi-liang Kwei and psychiatrists Adolf Meyer and David Kennedy Henderson, the paper describes the background conditions and planning for the hospital establishment and interprets the significance and value of Chi-liang Kwei's efforts to establish a psychiatric hospital from the perspective of the historic development of modern psychiatry in China.

Enzyme replacement therapy for mucopolysaccharidosis VI (Maroteaux-Lamy syndrome): experience in Hong Kong

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) is a very rare inherited lysosomal storage disease. We evaluated the efficacy and safety of weekly infusions of recombinant human arylsulfatase B as enzyme replacement therapy for two patients in whom this condition was advanced. The primary outcome variables were the distance walked in a 6-minute walk test, forced vital capacity, and ejection fraction. The secondary outcome variables were the number of stairs climbed in a 3-minute stair climbing test, joint mobility, urinary glycosaminoglycan excretion, auto-continuous positive airway pressure study and liver size. After 24 weeks of treatment, patient A walked 40 m (36%) and patient B walked 66 m (58%) more in the walk test than at baseline. After 48 weeks, in patient A the corresponding improvements were 142 m (129%) in the walk test and 33 stairs (60%) in the 3-minute stair climbing test, and in patient B the respective improvements were 198 m (174%) and 77 stairs (140%). There was a significant decline in urinary glycosaminoglycan excretion and improvement in range of motion of joints in both patients. The auto-continuous positive airway pressure study revealed improvements in patient A, while other efficacy variables remained static. There were no drug-related adverse events or allergic reactions reported during and after the infusions of recombinant human arylsulfatase B. Recombinant human arylsulfatase B significantly improves endurance and reduces urinary glycosaminoglycan excretion. The drug is generally safe and well tolerated.

Ruptured adrenocortical carcinoma as a cause of paediatric acute abdomen

Adrenocortical carcinoma (ACC) is rare in children. Its presentation is usually related to hormonal activity of the tumour. We report a case of childhood ACC that presented as an acute abdomen due to tumour rupture. This is the first reported case of a ruptured ACC as a cause of paediatric acute abdomen.

Phytosiderophores influence on cadmium mobilization and uptake by wheat and barley plants

A constant anthropogenic release of cadmium to the environment has resulted in a continuous buildup of Cd in soils. Uptake and accumulation of Cd in plant tissue and in grains may lead to food chain transfer to humans. Application of synthetic chelates was suggested to increase metal mobilization and facilitate phytoextraction as a means for the remediation of metal-polluted soils. However, most of the chelate-extracted metal may be leached rather than mobilized to plant roots. In contrast to the synthetic chelates added to soils, plant-produced chelators called phytosiderophores (PS) are excreted directly to the rhizosphere. Previous studies have shown that PS facilitate uptake of Zn and Fe by graminaceous plants. In this study, a two-step PS mediation of Cd uptake was hypothesized: (i) extraction and chelation in the soil solution, and (ii) delivery of the chelated Cd to the uptake system of the plant. We examined Cd extraction by PS, the synthetic chelate HEDTA [N-(2-hydroxyethyl)-ethylenediaminetriacetic acid], and a fungal siderophore rhizoferrin from solid-phase Cd phosphate at pH 7.3 with and without Fe competition in the presence of Ca and Mg as additional competing metals. While rhizoferrin did not extract Cd, PS and HEDTA did extract Cd even in the presence of Fe. Yet, uptake of Cd by wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) plants was not significantly influenced by Fe stress, but instead was controlled primarily by Cd2+ activity in solution. These results suggest that even though Cd may be mobilized by PS, there is no significant uptake of the Cd-PS complex by the plant roots.

Comprehensive chemical profiling of gramineous plant root exudates using high-resolution NMR and MS

Root exudates released into soil have important functions in mobilizing metal micronutrients and for causing selective enrichment of plant beneficial soil micro-organisms that colonize the rhizosphere. Analysis of plant root exudates typically has involved chromatographic methods that rely on a priori knowledge of which compounds might be present. In the research reported here, the combination of multinuclear and 2-D NMR with GC-MS and high-resolution MS provided de novo identification of a number of components directly in crude root exudates of different plant types. This approach was applied to examine the role of exudate metal ion ligands (MIL) in the acquisition of Cd and transition metals by barley and wheat. The exudation of mugineic acids and malate was enhanced by Fe deficiency. which in turn led to an increase in the tissue content of Cu, Mn, and Zn. The presence of elevated Cd maintained at a free activity pCd of 8.8 (10(-8.8) M), resulted in reduced phytosiderophore production by Fe deficient plants. The buffer morpholinoethane sulfonate (MES), which is commonly used in chelator-buffering nutrient solutions, was detected in the root exudate mixture, suggesting uptake and re-secretion of this compound by the roots. The ability to detect this compound in complex mixtures containing organic acids, amino acids, and other substances suggests that the analytical methods used here provide an unbiased method for simultaneous detection of all major components contained in root exudates.

Testicular volume of boys after inguinal herniotomy: combined clinical and radiological follow-up

A total of 173 boys aged 10 to 179 months with previous unilateral inguinal herniotomy were called back for follow-up. Clinical and ultrasound examinations of the scrotum were performed. The interval between operation and follow-up was 6 to 123 months (mean 31.68 months). One boy (0.58%) had a more than 50% and 10 (5.8%) had a more than 25% decrease in testicular volume on the operated side when compared with the non-operated side.

Analysis of phosphorylated metabolites in crayfish extracts by two-dimensional 1H-31P NMR heteronuclear total correlation spectroscopy (heteroTOCSY)

In vivo and extract analyses by one-dimensional 31P NMR have been a key tool in investigating energy-related metabolism. Although many phosphorylated metabolites have been observed, many of them have yet to be identified. This reflects the difficulty in identifying them using 31P NMR alone. Two-dimensional 1H-31P correlation experiments have been shown to be useful for assigning phosphorylated metabolites. To obtain better sensitivity and structure information, 1H-detected 31P-1H heteronuclear total correlation spectroscopy (heteroTOCSY) was implemented and a complete chemical shift assignment for a number of phosphorylated standards was made. The time courses of 1D heteroTOCSY signal intensity versus spin-locking time were established for these standards to aid the optimization of the 2D experiment. This method was applied to crayfish extracts for the assignment of glucose 6-phosphate, alpha-glycerophosphate, ribose 5-phosphate, fructose 1,6-bisphosphate, phosphocholine, phosphoethanolamine, glucose 1-phosphate, glycerophosphoethanolamine, glycerophosphocholine, ATP, ADP, and AMP. An alkyl phosphate, a hexose 1-phosphate, and a UDP-hexose were also observed. These assignments allowed the identification of many changes in the 31P NMR spectra of crayfish extracts elicited by treatment with the organophosphate pesticide chlorpyrifos. The assignment of an in vivo 31P spectrum of a live crayfish was also made based on the extract assignment. This approach should be a powerful tool for examining stress-associated changes in the metabolism of phosphorylated compounds.

Comprehensive analysis of organic ligands in whole root exudates using nuclear magnetic resonance and gas chromatography-mass spectrometry

Root exudates in the rhizosphere are vital to the normal life cycle of plants. A key factor is phytometallophores, which function in the nutritional acquisition of iron and zinc and are likely to be important in the uptake of pollutant metals by plants. Unraveling the biochemistry of these compounds is tedious using traditional analyses, which also fall short in providing the overall chemical composition or in detecting unknown or unexpected organic ligands in the exudates. Here, we demonstrate a comprehensive analysis of the exudate composition directly by 1H and 13C multidimensional NMR and silylation GC-MS. The advantages are (a) minimal sample preparation, with no loss of unknown compounds, and reduced net analysis time; (b) structure-based analysis for universal detection and identification; and (c) simultaneous analysis of a large number of constituents in a complex mixture. Using barley root exudates, a large number of common organic and amino acids were identified. Three derivatives of mugineic acid phytosiderophores were also determined, the major one being 3-epihydroxymugineic acid, for which complete 1H and 13C NMR assignments were obtained. Quantification of all major components using these methods revealed a sevenfold increase in total exudation under moderate iron deficiency, with 3-epihydroxymugineic acid comprising approximately 22% of the exudate mixture. As iron deficiency increased, total quantities of exudate per gram of root remained unchanged, but the relative quantity of carbon allocated to phytosiderophore increased to approximately 50% of the total exudate in response to severe iron deficiency.

In vivo 13C NMR analysis of acyl chain composition and organization of perirenal triacylglycerides in rats fed vegetable and fish oils

Lipid composition of body fat can be a key indicator of nutritional status and a number of human disorders. In vivo 13C NMR provides for repeated, noninvasive analysis of fatty acyl chain composition on individuals, which circumvents classical problems of individual variation and repetitive invasive sampling. It also offers a unique opportunity to examine acyl chain organization in situ. This approach was used to examine the fatty acyl chain composition in the perirenal fat pads of rats fed olive, safflower, and menhaden oil-containing diets. These changes were then monitored during a diet switch between olive and menhaden oil-fed rats. The fatty acid composition of perirenal fat pads and livers was also analyzed using gas chromatography for comparison with the in vivo NMR analysis. Both tissues assumed the general characteristics of diet fatty acyl chain and fatty acid composition and the diet switch induced a switchover of the perirenal composition in 30-45 days. These results indicate that a large portion of the diet fatty acyl chains were incorporated directly into adipose and liver tissues although some were also metabolized, particularly in menhaden oil-fed rats. Furthermore, changes in the in vivo spin-lattice relaxation times (T1) of fatty acyl carbons in the perirenal fat pads and their lipid extracts were followed and effective correlation times (tau eff) were calculated from the T1 data. The result indicated that the in vivo segmental mobility of acyl carbons was sensitive to changes in diet-derived fatty acyl chain composition and that the central region of the acyl chain was more sensitive to these changes. There was a qualitative similarity but quantitative differences in the tau eff of acyl carbons acquired in vivo and from extracts. These results suggest that adipose triacylglycerides experience an overall liquid-like microenvironment in vivo but with more restriction in their mobility, and that different factors may exist in governing their organization in situ versus in extracts.

Electrophoretic separation, characterization, and quantification of biologically active lignin-derived macromolecules

Degraded macromolecular lignin, which was isolated from the effluents of commercial pulp processing and known to inhibit early development in marine organisms, was separated and characterized using several polyacrylamide gel electrophoresis (PAGE) techniques. This lignin-derived macromolecule (LDM), when subjected to native PAGE and stained with alcian blue, appeared as a single band. On sodium dodecyl sulfate (SDS)-PAGE, LDM appeared to consist of two subcomponents with apparent molecular weights of 11 and < 1 kDa. When subjected to isoelectrofocusing--PAGE of pH 3-9, LDM consisted of two major bands in the basic region of the gel, with less distinct banding in the more acidic region. Two-dimensional PAGE of LDM indicated that the higher molecular weight subcomponent corresponded to the more basic constituents, while the lower molecular weight subcomponent corresponded to acidic constituents. When the two subcomponents of LDM were isolated from SDS gels by electroelution and assessed for their effects on successful fertilization and early development, the higher molecular weight subcomponent possessed most of the inhibitory activity. This is the first report of the application of a variety of electrophoretic techniques to both structurally and biologically characterize lignin-derived macromolecules.

Determination of metabolites by 1H NMR and GC: analysis for organic osmolytes in crude tissue extracts

World-wide salinity and drought problems necessitate the understanding of biological adaptation to water deficit. Osmotic adjustment via organic solutes is a common strategy for organisms to deal with water deficit problems. Numerous water-soluble organic metabolites across several chemical classes are commonly utilized as osmolytes, including betaines, sulfonium and sulfonate compounds, amino acids, carbohydrates, and polyols. To deal with the complexity and variability in osmolyte composition, we have devised an analytical approach that combines high-resolution 1H NMR and GLC to provide both structure identification and quantification of a broad spectrum of compounds. This combined approach also facilitated direct analyses of crude tissue extracts without extensive sample preparation, making it well-suited for a convenient screening of potential osmolytes. The structures of known osmolytes were confirmed from two-dimensional total correlation 1H NMR spectra, which also yielded structural information about unknown compounds. Five each terrestrial plant and marine animal species were examined for 41 metabolites, including osmolyte candidates glycinebetaine, dimethylsulfoniopropionate, taurine, proline, glycine, asparagine, alanine, glutamine, glucose, and sucrose. The osmotic function of glycinebetaine, proline, asparagine, glutamine, glucose, and sucrose was also demonstrated in leaves of Distichlis spicata under different salinity treatments.

Identification of glycerophosphorylcholine in mussel ovarian extracts by two-dimensional nuclear magnetic resonance

The abundance of the "phosphodiester" peak in differentiating or proliferating tissues, including reproductive organs and tumors, warrants further investigations of its metabolic role(s), which would require a rigorous confirmation of its identity. The assignment of this peak to glycerophosphorylcholine in 31P NMR spectra of biological samples has been largely based on chemical shift, which can result in ambiguities. We employed a combination of two-dimensional 31P-1H heteronuclear shift correlation and 1H total correlation spectroscopies to trace the spin connectivities of glycerophosphorylcholine and thus to identify its structure directly from crude ovarian extracts of mussels without ambiguities and the need for extensive purification. This approach can be applied generally to the identification of molecules containing heteroatoms in crude tissue extracts.

Temperature dependence of arginine kinase reaction in the tail muscle of live Sycionia ingentis as measured in vivo by 31P-NMR driven saturation transfer

We have employed the driven 31P-NMR saturation transfer method to measure in vivo the temperature dependence of the forward and reverse unidirectional fluxes of the arginine kinase reaction in the tail muscle of a live shrimp, Sycionia ingentis. Our results indicated that neither the forward nor the reverse rate constants of this reaction were significantly temperature-dependent between 8 and 16 degrees C, in contrast to the kinetic characteristics of isolated arginine kinases.

Hypoxia does not affect rate of ATP synthesis and energy metabolism in rice shoot tips as measured by 31P NMR in vivo

The cytoplasmic pH, concentrations of phosphate metabolites, and rate of ATP synthesis were measured in vivo in excised rice shoot tips under normoxic and hypoxic conditions using 31P NMR. When supplied with glucose, the shoot tips grew rapidly and were relatively unaffected by hypoxia. The cytoplasmic pH decreased transiently by only 0.2 units during hypoxia, and the concentration of ATP was maintained to at least 90% of the normoxic level. Most importantly, the unidirectional rate constant of ATP synthesis from free phosphate decreased less than 25% during hypoxia. This is in contrast to other actively growing tissues such as the maize root tip. gamma-Aminobutyrate was the major nonvolatile fermentation end product after 22 h of hypoxia. Other hypoxia-induced changes included a modest increase in [Ala] and [succinate] as well as a substantial decrease in [malate].

Emergence and recovery response of phosphate metabolites and intracellular pH in intact Mytilus edulis as examined in situ by in vivo 31P-NMR

We employed surface probe-localized 31P-NMR spectroscopy to examine in situ the impact of short-term emergence (hypoxia) and resubmergence on phosphate metabolites and intracellular pH (pHi) in intact mussels. The use of intact organisms ensured that all intrinsic responses remained active while monitoring of individuals minimized uncertainties resulting from stochastic behavior and other individual differences. The use of a photoetched, balanced-match foil probe combined with 1H-NMR images allowed 31P-NMR spectra to be acquired from the posterior adductor muscle with good signal-to-noise. Upon emergence, all mussels exhibited an increase in [Pi], a decline in [phosphoarginine] and pHi, and very little changes in [ATP] with time. The complementary behavior of [phosphoarginine] and [Pi] indicated a precursor-product relationship involved in the maintenance of [ATP] but the similarity between [phosphoarginine] and pHi time-courses cannot be so readily explained. Irregularity in the time-courses of some parameters could have reflected stochastic gaping activity. Resubmergence responses exhibited a reversal of the emergence responses, except that the pHi eventually became supraalkaline with irregular fluctuations. This might be related to the 'oxygen debt' phenomenon and increased oxidative phosphorylation.

Sublethal effects of pentachlorophenol in the abalone (Haliotis rufescens) as measured by in vivo 31P NMR spectroscopy

The sublethal biochemical effects of pentachlorophenol (PCP) were investigated in live, intact red abalones (Haliotis rufescens), using a flow-through exposure system, by in vivo 31P NMR spectroscopy. Based on rangefinding tests (6-hr LC50 = 1.6 mg/L; 6-hr no-observable-effect-level (NOEL) = 0.8 mg/L), three abalones were separately exposed to a sublethal concentration (1.2 mg/L) for 5 hr, followed by a 13 hr recovery period. Effects in foot muscle included both a decrease in phosphoarginine and an increase in inorganic monophosphate concentrations ([PA] and [Pi], respectively); both foot muscle concentrations of adenosine triphosphate [ATP] and intracellular pH (pHi) also declined. Parallel in vitro experiments revealed that concentrations of glycerol 3-phosphate, lactate, citrate, succinate, malate, and alanine (Ala) all increased, while those of glyceraldehyde 3-phosphate and glutamine (Gln) remained stable. Also, these effects were not evident until 2 hr into exposure, possibly the time required for PCP to attain an effective concentration in foot muscle. During recovery, while Pi declined to pre-exposure levels, [PA] completely recovered in only one individual. Also, realkalinization of pHi was similar to recovery of [Pi], and ATP returned to near-initial levels, as did glycerol 3-phosphate, lactate, succinate, malate, and Ala; glyceraldehyde 3-phosphate, citrate, and Gln levels declined. Recovery responses corresponded to the time for PCP clearance from foot muscle. The effects of PCP were similar to those of hypoxia, fatigue, hypersalinity, and arginine kinase inhibitors, and so sublethal PCP concentrations may also inhibit electron transport and arginine kinase as well as uncouple mitochondrial oxidative phosphorylation in intact molluscs. Thus, the effects of pollutants on key biochemical processes may now be measured in intact aquatic organisms as they occur, improving our ability to accurately assess the environmental effects of pollutants in the laboratory.

In vivo 23Na and 31P NMR measurement of a tonoplast Na+/H+ exchange process and its characteristics in two barley cultivars

A Na+ uptake-associated vacuolar alkalinization was observed in roots of two barley cultivars (Arivat and the more salt-tolerant California Mariout) by using 23Na and 31P in vivo NMR spectroscopy. A NaCl uptake-associated broadening was also noted for both vacuolar Pi and intracellular Na NMR peaks, consistent with Na+ uptake into the same compartment as the vacuolar Pi. A close coupling of Na+ with H+ transport (presumably the Na+/H+ antiport) in vivo was evidenced by qualitative and quantitative correlations between Na+ accumulation and vacuolar alkalinization for both cultivars. Prolongation of the low NaCl pretreatment (30 mM) increased the activity of the putative antiport in Arivat but reduced it in California Mariout. This putative antiport also showed a dependence on NaCl concentration for California Mariout but not for Arivat. No cytoplasmic acidification accompanied the antiporter activity for either cultivar. The response of adenosine phosphates indicated that ATP utilization exceeded the capacity for ATP synthesis in Arivat, but the two processes seemed balanced in California Mariout. These comparisons provide clues to the role of the tonoplast Na+/H+ antiport and compensatory cytoplasmic adjustments including pH, osmolytes, and energy phosphates in governing the different salt tolerance of the two cultivars.

Monitoring of metabolic responses of intact Haliotis (abalones) under salinity stress by 31P surface probe localized NMR

Surface probe localized 31P NMR spectroscopy was employed to record the metabolic responses of the foot of intact Haliotis cracherodii and H. rufescens (black and red abalones) under hyper- and hypoosmotic stresses. Use of the surface probe allowed spectral localization on the foot of intact abalones, facilitated monitoring of different sizes of animals, and minimized constraints on aquatic chamber design normally imposed by homogeneous-field probes. Generally, hyperosmotic stress (51%) elicited more rapid changes of phosphate metabolites than hypoosmotic stress (17%). As with the well-studied hypoxic stress in intact mammalian and excised molluscan tissue, both salinity treatments caused drops in the phosphagen and increases in inorganic phosphate levels. However, osmotic stress was distinct from hypoxic stress in that intracellular pH did not change and nucleotide triphosphate (NTP) concentrations dropped immediately. Although these findings are preliminary, they demonstrate the utility of the surface probe approach for studies of environmental stress in intact marine invertebrates.

An in vivo 1H and 31P NMR investigation of the effect of nitrate on hypoxic metabolism in maize roots

The effect of nitrate on the short-term hypoxic response and recovery of flooded mature maize roots has been investigated in vivo by 1H and 31P NMR and in vitro by 1H NMR and gas chromatography-mass spectrometry. Employing 1H NMR in addition to 31P NMR extended the number of identifiable compounds in vivo from 4 to 15, while in vitro two-dimensional NMR and gas chromatography-mass spectrometry aided rigorous in vivo 1H NMR resonance assignments and quantitation of 24 compounds. In the absence of nitrate, the concentrations of key metabolites including alanine, ethanol, gamma-aminobutyrate, lactate, succinate, and sucrose changed during 8 h of hypoxia in a manner consistent with reduced tricarboxylic acid cycle activity and diversion to glycolytic fermentation. The pH drop in the cytoplasm during hypoxia was rapid, about 0.2 unit, and diminished quickly upon recovery. Rapid recovery of ethanol, succinate, and sucrose levels was also observed, which indicates a return to normal aerobic metabolism. Although the hypoxic response itself, including pH, was not greatly affected by the presence of nitrate, nitrate reduced the amount of fermentation end products produced, helped maintain a higher free NTP concentration during hypoxia, and increased the rate of overall recovery from hypoxia. These findings suggest the presence of a nitrate-induced maintenance-level respiration in hypoxic maize roots, which helps explain the protection imparted by nitrate to flooded hypoxic maize plants.

Monitoring of hypoxic metabolism in superfused plant tissues by in vivo 1H NMR

We have used a coaxial superfusion system to obtain physiologically interpretable in vivo 1H NMR spectra at 500 MHz of carrot roots, maize roots, and rice shoots in water (no 2H2O). The superfusion system was constructed from common laboratory parts, required no modification of the probe and sample loading procedure, and was inherently leak resistant. The assignment and quantitation of the in vivo 1H NMR resonances were achieved by performing two-dimensional NMR experiments in vivo, and by in vitro analysis including NMR and gas chromatography-mass spectrometry. The in vivo spectra were dominated by resonances arising from sugars, organic acids, amino acids, and ethanol. In vivo measurements of spin-lattice relaxation times and chemical shifts of beta protons of malate in carrot roots suggested that malate was located in a relatively viscous and acidic compartment. In rice shoots, the hypoxic time courses of 9 metabolites were established in vivo, and 23 in vitro. In both cases, accumulation of lactate, ethanol, Ala, and gamma-aminobutyrate as well as a decrease in Gln and Asn concentrations were observed. These findings are consistent with accelerated glycolysis and decreased tricarboxylic acid cycle activity.

Combined use of 1H-NMR and GC-MS for metabolite monitoring and in vivo 1H-NMR assignments

Thirty-three metabolites were observed in perchloric acid extracts of four different tissues by in vitro 1H-NMR, GC-MS and alcohol dehydrogenase assay, and the information was used to interpret an in vivo two-dimensional nuclear Overhauser effect 1H-NMR spectrum. The metabolite profiles of the different tissues indicate a number of potential tissue-specific markers: N-acetylaspartate and gamma-aminobutyric acid for rat brain, glutamine/glutamic acid ratio for dog heart, arginine and sucrose for carrot, and t-aconitate, sucrose, asparagine/aspartic acid concentration ratios for corn roots. gamma-Aminobutyric acid and malate can be regarded as metabolic indicators for stressed corn roots. Concentrations of threonine and valine in corn roots were constant under hypoxic and salt stress, and can serve as internal standards for both in vivo and in vitro NMR studies. The in vitro information was further used to identify 12 compounds from the in vivo 1H-NMR spectra (including the two-dimensional nuclear Overhauser effect spectrum) of a carrot cylinder by correlating the chemical shift and nuclear Overhauser effect information. Thus, our choice of methods with a capability for structural determination allows the characterization of complex tissue extracts with minimum sample preparation, and supports, as well as complements, in vivo 1H-NMR investigations of metabolism.

Isolation and characterization of two cyanogenic beta-glucosidases from flax seeds

Two cyanogenic beta-glucosidases, linustatinase and linamarase, were isolated and purified from flax seeds (Linum ussitatissimum). They catalyze the sequential hydrolysis of linustatin and neolinustatin to yield acetone and methylethyl ketone cyanohydrins, respectively. The purification procedure for linustatinase involved acetone extraction, precipitation by polyethyleneimine and ammonium sulfate (40-80% saturation), and Red A gel, concanavalin A-Sepharose, and PBE 94 column chromatography; that for linamarase was similar except that polyethyleneimine precipitation was eliminated and DE-52 and Sepharose CL-6B replaced Red A gel column chromatography. The native substrates neolinustatin and linamarin were used for the assay during purification. Both proteins were purified to electrophoretic homogeneity. Linustatinase is an alpha beta dimer (molecular weights of alpha and beta = 39,000 and 19,000, respectively) while linamarase appears to be an alpha 5 beta 5 decamer (molecular weights of alpha and beta = 62,500 and 65,000, respectively). Both enzymes contain mannose or glucose. Linustatinase exists in five different isozymic forms (isoelectric points between 7 and 8) whereas linamarase occurs in one major form (isoelectric point 4 to 5). The kinetic parameters of the two enzymes are similar: acidic pH optima, Km's in the millimolar range, and competitive inhibition by delta-gluconolactone, a transition state analog. The presence of an aglycone structure in the substrates is important for both enzyme activities. In addition, both enzymes are specific towards the beta-glycosidic linkage; linustatinase (a beta-bis-glucosidase) readily hydrolyzes beta-bis-glucosides with 1,6 and 1,3 linkages whereas linamarase (a beta-monoglucosidase) exhibits little activity towards these substrates.