Universal HbA1c Measurement in Early Pregnancy to Detect Type 2 Diabetes Reduces Ethnic Disparities in Antenatal Diabetes Screening: A Population-Based Observational Study.

In response to the type 2 diabetes epidemic, measuring HbA1c with the first-antenatal blood screen was recently recommended in NZ. This would enable prompt treatment of women with unrecognised type 2 diabetes, who may otherwise go undetected until the gestational diabetes (GDM) screen. We compare inter-ethnic antenatal screening practices to examine whether the HbA1c test would be accessed by ethnicities most at risk of diabetes, and we determined the prevalence of unrecognised type 2 diabetes and prediabetes in our pregnant population. This is an observational study of pregnancies in Christchurch NZ during 2008-2010. Utilising electronic databases, we matched maternal characteristics to first-antenatal bloods, HbA1c, and GDM screens (glucose challenge tests and oral glucose tolerance tests). Overall uptake of the first-antenatal bloods versus GDM screening was 83.1% and 53.8% respectively in 11,580 pregnancies. GDM screening was lowest in Maori 39.3%, incidence proportion ratio (IPR) 0.77 (0.71, 0.84) compared with Europeans. By including HbA1c with the first-antenatal bloods, the number screened for diabetes increases by 28.5% in Europeans, 40.0% in Maori, 28.1% in Pacific People, and 26.7% in 'Others' (majority of Asian descent). The combined prevalence of unrecognised type 2 diabetes and prediabetes by NZ criteria, HbA1c ≥5.9% (41mmol/mol), was 2.1% in Europeans, Maori 4.7% IPR 2.59 (1.71, 3.93), Pacific People 9.5% IPR 4.76 (3.10, 7.30), and 'Others' 6.2% IPR 2.99 (2.19, 4.07). Applying these prevalence data to 2013 NZ national births data, routine antenatal HbA1c testing could have identified type 2 diabetes in 0.44% and prediabetes in 3.96% of women. Routine HbA1c measurement in early pregnancy is an ideal screening opportunity, particularly benefitting vulnerable groups, reducing ethnic disparities in antenatal diabetes screening. This approach is likely to have world-wide relevance and applicability. Further research is underway to establish whether, as for type 2 diabetes, prompt treatment of prediabetes improves pregnancy and neonatal outcomes.

Women with an HbA1c of 41-49 mmol/mol (5.9-6.6%): a higher risk subgroup that may benefit from early pregnancy intervention.

AIMS: To examine whether women with an HbA1c of 41-49 mmol/mol (5.9-6.6%) at diagnosis of gestational diabetes are higher risk than women with an HbA1c of < 41 mmol/mol (5.9%) and whether pregnancy outcomes are improved if treated at < 24 weeks' gestation. METHODS: This was an observational study of women with gestational diabetes diagnosed by early HbA1c screening or subsequent oral glucose tolerance test at < 34 weeks' gestation who delivered at National Women's Health, Auckland, from July 2012 to June 2014. Data were extracted from the hospital database. Women with HbA1c 41-49 mmol/mol (5.9-6.6%) were divided into those seen < 24 weeks (Early, n = 134) and those seen ≥ 24 weeks (Later, n = 151). Those with HbA1c < 41 mmol/mol (5.9%) were labelled Other GDM (n = 661). RESULTS: The Early and Later groups, compared with Other GDM, had more Polynesian and fewer (non-Indian) Asian women, higher BMI and more required medication (P < 0.001). More were smokers (P = 0.007, 0.02) and more had chronic hypertension (P < 0.001, 0.02). There were higher rates of adverse outcomes in the Later group than the Other GDM group (pre-eclampsia 8.0% vs. 2.4%, P = 0.001, preterm birth 16.6% vs. 8.2%, P = 0.002, neonatal admission 15.5% vs. 9.2%, P = 0.02). Outcomes were similar between the Early group and Other GDM group (pre-eclampsia 1.5% vs. 2.4%, P = 0.5, preterm birth 10.5% vs. 8.2% P = 0.4, neonatal admission 13.6% vs. 9.2%, P = 0.12). Comparing the Early and Later groups, the Early group had less pre-eclampsia, 1.5% vs. 8.0%, adjusted P = 0.03. Other outcomes were not statistically different. CONCLUSIONS: An HbA1c of 41-49 mmol/mol (5.9-6.7%) identifies a higher-risk group of women with gestational diabetes. Overall, our data support early treatment of women with an HbA1c ≥ 41 mmol/mol (5.9%).

Pregnancy in women with Type 2 diabetes: who takes metformin and what is the outcome?

AIMS: To review pregnancy outcomes in women with Type 2 diabetes (Type 2 DM), comparing women treated with those not treated with metformin. METHODS: Data were collected by case-note review for all pregnancies in women with Type 2 DM over a 6-year period (1998-2003) at the National Women's Hospital. Two hundred and fourteen pregnancies were included, metformin was taken in 93 pregnancies and continued until delivery in 32; the remaining 121 pregnancies comprised the control group. The principal outcome measures were preeclampsia, perinatal loss and neonatal morbidity. RESULTS: Baseline characteristics differed between groups: women in the metformin group had greater mean (SD) body mass index [35.5(7.6) vs. 33.5(6.6) kg/m2, P < 0.05], more chronic hypertension (19% vs. 7%, P < 0.05) and higher mean (SD) first trimester glycated haemoglobin (HbA1c) levels [8.3(1.9)% vs. 7.5(1.7)%, P < 0.005]. There was no difference between metformin and control groups, respectively, in the rate of preeclampsia (13% vs. 14%, P = 0.84), perinatal loss (3% vs. 2%, P = 0.65) or neonatal morbidity, including rate of prematurity (23% vs. 22%, P = 0.7), admission to the neonatal unit (40% vs. 48%, P = 0.27), respiratory distress (9% vs. 18%, P = 0.07) and treatment with intravenous dextrose (20% vs. 31%, P = 0.08). CONCLUSIONS: Pregnant women with Type 2 DM who were treated with metformin had more risk factors for adverse pregnancy outcomes, but no differences in outcomes were seen compared with women not taking metformin. We need randomized trials to address potential benefits of metformin treatment in this population that may be masked by current practice.

Effect of pregnancy on the pharmacokinetics of metformin.

AIMS: To determine the effects of pregnancy on metformin pharmacokinetics. METHODS: Seven women with Type 2 diabetes mellitus taking metformin throughout pregnancy were studied on two occasions, once at 28-36 weeks gestation and once at least 8 weeks postpartum. Serum metformin concentrations were determined across a dosing interval using high-performance liquid chromatography. The areas under the serum concentration-time curve from 0 to 4 h post-dose (AUC0-4) and 0 to 8 h post-dose (AUC0-8) where possible, were compared in the pregnant and non-pregnant state. RESULTS: Metformin concentrations were lower in pregnancy in six subjects, with a mean (95% CI) AUC0-4 that was 69% (53.6, 84.8) of the postpartum value. The AUC0-4 of one subject was higher in pregnancy at 142% of the postpartum value. Overall, the mean (95% CI) AUC0-4 during pregnancy for all seven subjects was 80% (51.3, 107.8) of the postpartum value (P = 0.053, two-tailed t-test; P = 0.027, one-tailed t-test). CONCLUSION: These results are consistent with our hypothesis that the clearance of metformin increases in pregnancy as a result of enhanced renal elimination. A larger study is required to establish whether metformin dose adjustments are required in late pregnancy to maintain therapeutic effect.

An evaluation of the modified Airway Management Device.

We evaluated the modified Airway Management Device (AMDTM) in 60 spontaneously breathing anaesthetised patients. The insertion and removal of the device was very easy and atraumatic. The airway was secured on the first attempt in 41 patients (70%; 95% CI 57-80%). The most important problem was loss of airway, which occurred in 11 patients (19%; 11-30%) during maintenance of anaesthesia. The AMD was dislodged during maintenance in one patient. There was a loss of the airway in 12 patients (20%; 12-31%); in 10, it was maintained with simple airway manoeuvres or a laryngeal mask airway and tracheal intubation was required in two patients. Ten of these patients were male and two were female; the failure rate was 33% (12-31%) among the male patients and 6% (2-22%) among the female patients. The cuff volumes ranged from 4 ml to 80 ml and cuff pressures from 6 cm H2O to 92 cm H2O. Blood was seen on removal in three patients (6%; 2-16%) and nine patients (18%; 10-30%) experienced sore throat after removal of the device.

Galectins as modulators of cell adhesion.

The galectins are a family of carbohydrate-binding proteins that are distributed widely in metazoan organisms. Each galectin exhibits a specific pattern of expression in various cells and tissues, and expression is often closely regulated during development. Although these proteins are found mainly in the cell cytoplasm, some are secreted from cells and interact with appropriately glycosylated proteins at the cell surface or within the extracellular matrix. These receptors include cell-adhesion molecules such as integrins, and matrix glycoproteins such as laminin and fibronectin isoforms. Recent studies have increased understanding of the roles of the galectins in regulating cell-cell and cell-matrix adhesion. These interactions are critically involved in modulation of normal cellular motility and polarity and during tissue formation, and loss of adhesive function is implicated in several disease states including tumour progression, inflammation and cystic development in branching epithelia such as kidney tubules. This review discusses recent progress in defining the specificities and mechanisms of action of secreted galectins as multifunctional cell regulators.

An asymmetric approach to spirocylic systems: a formal synthesis of zizaene.

A general route to enantiopure spirocarbocycles is described. The use of various chiral bicyclic lactams 1 that have been doubly alkylated with olefinic halides gives good yields of alpha,alpha-disubstituted chiral lactams 2 which were cyclized to spiro-olefins using ring closure metathesis methodology (Grubbs' catalyst). These spirolactams 3, formed in generally excellent yields, were shown to be smoothly transformed into spirocyclopentenone 6, spirocyclohexenone, 7, and spirolactams 8. Further demonstration of this spirocyclization methodology was featured in a formal synthesis of zizaene, by preparing in enantiomeric form the Coates' intermediate 21. This synthetic effort provided additional examples of the synthetic versatility of chiral bicyclic lactams 2a,b.

NMR solution studies of hamster galectin-3 and electron microscopic visualization of surface-adsorbed complexes: evidence for interactions between the N- and C-terminal domains.

Galectin-3, a beta-galactoside binding protein, contains a C-terminal carbohydrate recognition domain (CRD) and an N-terminal domain that includes several repeats of a proline-tyrosine-glycine-rich motif. Earlier work based on a crystal structure of human galectin-3 CRD, and modeling and mutagenesis studies of the closely homologous hamster galectin-3, suggested that N-terminal tail residues immediately preceding the CRD might interfere with the canonical subunit interaction site of dimeric galectin-1 and -2, explaining the monomeric status of galectin-3 in solution. Here we describe high-resolution NMR studies of hamster galectin-3 (residues 1--245) and several of its fragments. The results indicate that the recombinant N-terminal fragment Delta 126--245 (residues 1--125) is an unfolded, extended structure. However, in the intact galectin-3 and fragment Delta 1--93 (residues 94--245), N-terminal domain residues lying between positions 94 and 113 have significantly reduced mobility values compared with those expected for bulk N-terminal tail residues, consistent with an interaction of this segment with the CRD domain. In contrast to the monomeric status of galectin-3 (and fragment Delta 1--93) in solution, electron microscopy of negatively stained and rotary shadowed samples of hamster galectin-3 as well as the CRD fragment Delta 1--103 (residues 104--245) show the presence of a significant proportion (up to 30%) of oligomers. Similar imaging of the N-terminal tail fragment Delta 126--245 reveals the presence of fibrils formed by intermolecular interactions between extended polypeptide subunits. Oligomerization of substratum-adsorbed galectin-3, through N- and C-terminal domain interactions, could be relevant to the positive cooperativity observed in binding of the lectin to immobilized multiglycosylated proteins such as laminin.

Molecular modeling and mutagenesis studies of the N-terminal domains of galectin-3: evidence for participation with the C-terminal carbohydrate recognition domain in oligosaccharide binding.

A model structure (Henrick,K., Bawumia,S., Barboni,E.A.M., Mehul,B. and Hughes, R.C. (1998) Glycobiology:, 8, 45-57) of the carbohydrate recognition domain (CRD, amino acid residues 114-245) of hamster galectin-3 has been extended to include N-terminal domain amino acid residues 91-113 containing one of the nine proline-rich motifs present in full-length hamster galectin-3. The modeling predicts two configurations of the N-terminal tail: in one the tail turns toward the first (SI) and last (S12) beta-strands of the CRD and lies at the apolar dimer interface observed for galectins -1 and -2. In the second folding arrangement the N-terminal tail lies across the carbohydrate-binding pocket of the CRD where it could participate in sugar-binding: in particular tyrosine 102 and adjacent residues may interact with the partly solvent exposed nonreducing N-acetylgalactosamine and fucose substituents of the A-blood group structure GalNAcalpha1,3 [Fucalpha1,2]Galbeta1,4GlcNAc-R. Binding studies using surface plasmon resonance of a recombinant fragment Delta1-93 protein containing residues 94-245 of hamster galectin-3 and a collagenase-derived fragment Delta1-103 containing residues 104-245, as well as alanine mutagenesis of residues 101-105 in Delta1-93 protein, support the prediction that Tyr102 and adjacent residues make significant contributions to oligosaccharide binding.

Nuclear localisation of wild type and mutant galectin-3 in transfected cells.

Galectin-3, a member of a family of carbohydrate-binding proteins, is present generally in the cytoplasm of cells. However, galectin 3 can also be located in nuclei under certain conditions although it lacks any known nuclear localisation signal and the mechanism by which the protein is sequestered in nuclei is unknown. Here we describe that Cos-7 cells or rabbit smooth muscle Rb-1 cells transfected with cDNA encoding hamster galectin-3 sequester the protein in nuclei whereas untransfected BHK cells expressing the endogenous hamster lectin or transfected BHK cells over-expressing the protein, do not. Confocal immunofluorescence microscopy of Cos-7 cells or rabbit smooth muscle Rb-1 cells transfected with cDNAs encoding mutants of hamster galectin-3 containing N-terminal or internal deletions shows that nuclear localisation does not require the first 103 amino acid residues of the protein. Further deletion of residues 104-110 dramatically prevents sequestration in nuclei. However, the sequence A104PTGALT110 by itself is not obligatory for nuclear localisation and can be substituted by other unrelated sequences. A truncated galectin-3 protein, that is blocked in nuclear expression, retains carbohydrate-binding activity, making less likely the possibility that severe N-terminal truncations of galectin-3 induce mis-folding leading to aggregation and cytoplasmic sequestration and an incidental effect on nuclear trafficking. These studies indicate that nuclear import and retention of galectin-3 is a property of the CRD domain and is independent of N-terminal domains that others have shown to contain binding domains for various nuclear components.

Interaction of a novel cysteine and histidine-rich cytoplasmic protein with galectin-3 in a carbohydrate-independent manner.

We have used the yeast two-hybrid system to search for cytoplasmic proteins that might assist in the intracellular trafficking of the soluble beta-galactoside-binding protein, galectin-3. We utilised as bait murine full-length galectin-3 to screen a murine 3T3 cDNA library. Several interacting clones were found to encode a partial open reading frame and a full-length clone was obtained by rapid amplification of cDNA ends methodology. In various assays in vitro the novel protein was shown to bind galectin-3 in a carbohydrate-independent manner. The novel protein contains an unusually high content of cysteine and histidine residues and shows significant sequence homologies with several metal ion-binding motifs present in known proteins. Confocal immunofluorescence microscopy of permeabilised 3T3 cells shows a prominent perinuclear, as well as cytoplasmic, localisation of the novel protein.

So what do your sugars do?

Up to about fifteen years ago the above question was quite often asked of glycoconjugates enthusiasts. It was always a silly question, the answer being 'How many doings do you want to hear about?' Since then our understanding of the structures, biosynthesis and varied functions of the glycoconjugates has developed incredibly and come to have a major impact on much of present-day biological and medical research.

Secretion of the galectin family of mammalian carbohydrate-binding proteins.

Galectins are cytosolic proteins that lack any signal sequence for transport into the endoplasmic reticulum and are not glycosylated, although several galectins contain consensus sites for N-glycosylation, indicating that these proteins do not traverse the ER-Golgi network. However, there is abundant evidence for the extracellular localisation of some galectins at cell surfaces, in the extracellular matrix and in cell secretions consistent with other evidence for extracellular roles of galectins as modulators of cell adhesion and signalling. How then are galectins secreted if not through the classical secretory pathway? Do all galectins share the same secretory pathway? Can a particular galectin utilise more than one secretory pathway? If galectins play important extracellular roles how is their secretion regulated in relation to function? These are still largely unanswered questions but recent studies are beginning to give glimpses into some novel aspects of the secretion of these intriguing proteins.

Determinants in the N-terminal domains of galectin-3 for secretion by a novel pathway circumventing the endoplasmic reticulum-Golgi complex.

Galectin-3 is a beta-galactoside-binding protein that is secreted from many cells although the protein lacks a signal sequence for transfer into the endoplasmic reticulum and Golgi compartments and entry into classical secretory pathways. Previously it was shown that attachment of the first 120 amino acid residues of the N-terminal sequence of hamster galectin-3 to the cytoplasmic protein chloramphenicol acetyltransferase (CAT) supported the rapid secretion of the fusion protein from transiently transfected Cos cells under conditions in which CAT protein was not secreted. Here we report that progressive N-terminal truncation gradually reduced secretion of the fusion proteins, eventually to very low levels compared with the starting product, but did not totally eliminate secretion until a significant majority of the sequence was removed. Mutant CAT fusion proteins containing internal deletions in residues 97-120 of the galectin-3 N-terminal sequence were also secreted to a similar extent to the starting product, but further deletion of residues 89-96 abolished detectable secretion. Proline to alanine mutagenesis of the sequence YP(90)SAP(93)GAY in two secretion-competent CAT fusion proteins greatly reduced or abolished their secretion, whereas similar mutagenesis of proline pairings present elsewhere in the galectin-3 N-terminal segments of these proteins had no effect. The results indicate that this sequence is one essential determinant for secretion of galectin-3-CAT fusion proteins and by inference galectin-3, at least from transfected Cos cells. However, the short sequence of residues 89-96 by itself is insufficient to direct secretion of CAT fusion proteins and appears to be active only in the context of a larger portion of the galectin-3 N-terminal sequence.

Galectin-3 modulates rat mesangial cell proliferation and matrix synthesis during experimental glomerulonephritis induced by anti-Thy1.1 antibodies.

Galectin-3 is a beta-galactoside-binding protein synthesized by macrophages and other inflammatory cells and expressed in various branching epithelia, including the developing kidney. The expression of galectin-3 has been studied in a rat model of acute mesangial proliferative glomerulonephritis in which a single injection of anti-Thy1.1 antibodies leads to destruction of mesangial cells expressing a Thy1.1 epitope on their surface. The glomerular lesion is characterized by expansion of the mesangial matrix, especially laminin and collagen type IV, and mesangial hypercellularity. Galectin-3 expression, which is sparse in mature rat kidney and confined to the apical face of some distal tubules, is increased within 1-3 days following antibody administration, with the recruitment of glomerular macrophages and pronounced neo-expression in the cytoplasm and at the basal face of distal tubules. At later times, galectin-3 is detected immunohistochemically in the repopulating mesangial cell mass, preceding the extensive mesangial deposition of laminin and collagen type IV. Mesangial cells in culture do not produce appreciable amounts of galectin-3 but do bind and endocytose exogenously added lectin. Addition of galectin-3 to primary cultures of mesangial cells prepared from normal rats induces a 1.5-fold increase in the synthesis of collagen type IV and it also acts in synergy with a quantitatively similar stimulatory effect of transforming growth factor beta (TGF-beta) on matrix synthesis. Exogenous galectin-3 prolongs the survival of mesangial cells in serum-free cultures and also protects these cells against cytotoxic effects of TGF-beta. The data support the notion that the increased expression and secretion of galectin-3 in infiltrating macrophages and in distal tubular epithelia, together with up-regulation of IL-1beta and TGF-beta genes, play a role in mesangial hypercellularity in the progression of one model of inflammatory renal disease.

Galectin-3 and polarized growth within collagen gels of wild-type and ricin-resistant MDCK renal epithelial cells.

Previous studies (Q. Bao and R. C. Hughes (1995) J. Cell Sci., 108, 2791-2800) showed that the beta-galactoside-binding protein, galectin-3, is secreted onto the basolateral surface domains of Madin-Darby canine kidney MDCK cells growing as polarized cysts within a collagen gel. The growth and enlargement of such cysts were shown to be increased significantly when cultured in the presence of antibodies directed against the lectin and were slowed down by addition of exogenous galectin-3. These results suggested a role for galectin-3, interacting with appropriately glycosylated surface receptors, as a negative growth regulator in the development of MDCK cysts, a well-known model for renal epithelial morphogenesis. In the present report we have tested this proposal by use of a ricin-resistant mutant of MDCK cells that is unable to transfer galactose residues during biosynthesis of cellular glycoconjugates and hence lacks extracellular receptors for galectin-3. We find that when grown within collagen gels, the mutant cell cysts grow significantly faster than wild-type cell cysts. Furthermore, they form nonspherical and tubular cysts that are induced in wild-type cell cysts only under the influence of the morphogen, hepatocyte growth factor (HGF).

Kinetic measurements of binding of galectin 3 to a laminin substratum.

Galectin 3, a beta-galactoside binding protein, contains a C-terminal carbohydrate recognition domain (CRD) and an N-terminal segment including multiple repeats of a proline/tyrosine/glycine-rich motif. Previous work has shown that galectin 3 but not the isolated CRD binds to laminin, a multivalent ligand, with positive cooperativety indicating the formation of multiple interactions although the lectin in solution is monomeric. Using surface plasmon resonance, we find that hamster galectin 3 at sub-micromolar concentrations or its isolated CRD at all concentrations binds to a laminin substratum with similar association (k(ass); 10-30,000 M(-1) S(-1)) and dissociation (k(diss); 0.2-0.3 S1(-1)) rates and weak affinity (Ka; 1-3 x 10(5) M(-1)). At higher concentrations of galectin 3 the off rate decreases ten fold leading to increased affinity. Ligation of an N-terminal epitope of galectin 3 with a monoclonal Fab fragment increases association and dissociation rates ten fold. A recombinant protein obtained by deletion of the first 93 N-terminal residues binds to laminin with positive cooperativity and a slowly dissociating fraction (K(diss); 0.002 S(-1)) accumulates on the substratum. The data suggest that homophilic interactions between CRD as well as N terminal domains are implicated in galectin 3 aggregation on the substratum leading to positive binding cooperativity.

Evidence for subsites in the galectins involved in sugar binding at the nonreducing end of the central galactose of oligosaccharide ligands: sequence analysis, homology modeling and mutagenesis studies of hamster galectin-3.

A model of the carbohydrate recognition domain CRD, residues 111-245, of hamster galectin-3 has been made using homology modeling and dynamics minimization methods. The model is based on the known x-ray structures of bovine galectin-1 and human galectin-2. The oligosaccharides NeuNAc-alpha2,3-Gal-beta1,4-Glc and GalNAc-alpha1, 3-[Fuc-alpha1,2]-Gal-beta1,4-Glc, known to be specific high-affinity ligands for galectin-3, as well as lactose recognized by all galectins were docked in the galectin-3 CRD model structure and a minimized binding conformation found in each case. These studies indicate a putative extended carbohydrate-binding subsite in the hamster galectin-3 involving Arg139, Glu230, and Ser232 for NeuNAc-alpha2,3-; Arg139 and Glu160 for fucose-alpha1,2-; and Arg139 and Ile141 for GalNAc-alpha1,3- substituents on the primary galactose. Each of these positions is variable within the whole galectin family. Two of these residues, Arg139 and Ser232, were selected for mutagenesis to probe their importance in this newly identified putative subsite. Residue 139 adopts main-chain dihedral angles characteristic of an isolated bridge structural feature, while residue 232 is the C-terminal residue of beta-strand-11, and is followed immediately by an inverse gamma-turn. A systematic series of mutant proteins have been prepared to represent the residue variation present in the aligned sequences of galectins-1, -2, and -3. Minimized docked models were generated for each mutant in complex with NeuNAc-alpha2,3-Gal-beta1,4-Glc, GalNAc-alpha1, 3-[Fuc-alpha1,2]-Gal-beta1,4- Glc, and Gal-beta1,4-Glc. Correlation of the computed protein-carbohydrate interaction energies for each lectin-oligosaccharide pair with the experimentally determined binding affinities for fetuin and asialofetuin or the relative potencies of lactose and sialyllactose in inhibiting binding to asiolofetuin is consistent with the postulated key importance of Arg139 in recognition of the extended sialylated ligand.

The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II and a solution-based assay for the binding of a biantennary glycopeptide.

The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J. 11, 299-303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (lambda[ex] = 295 nm, lambda[em] = 350 nm) decay is complex and can be described by four decay times with the following values: tau1 = 7.4 nsec, alpha1 = 0.22; tau2 = 2.9 nsec, alpha2 = 0.25: tau3 = 1.0 nsec, alpha3 = 0.34, tau4 = 0.2 nsec, alpha4 = 0.18. The addition of a biantennary glycopeptide (carbohydrate sequence [see text]) to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8 x 10(5) M(-1). The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein.