TUGraz OPEN Library

Holzinger, Andreas

Zupan, Mario

KNODWAT: A scientific framework application for testing knowledge discovery methods for the biomedical domain

Partl, Christian

Lex, Alexander

Streit, Marc

Kalkofen, Denis

Kashofer, Karl

Schmalstieg, Dieter

enRoute: dynamic path extraction from biological pathway maps for exploring heterogeneous experimental datasets

Mehrer, Helmut

Luckabauer, Martin

Sprengel, Wolfgang

Self- and Solute Diffusion, Interdiffusion and Thermal Vacancies in the System Iron-Aluminum

Coclite, Anna Maria

Shi, Yujun

Gleason, Karen K.

 Physics Procedia  46 ( 2013 )  56 – 61 
1875-3892 © 2013 The Authors. Published by Elsevier B.V.
Selection and peer-review under responsibility of Organizing Committee of EUROCVD 19.
doi: 10.1016/j.phpro.2013.07.045 
Nineteenth European Conference on Chemical Vapor Deposition, (EUROCVD 19) 
Super-Hydrophobic and Oloephobic Crystalline Coatings by 
Initiated Chemical Vapor Deposition 
Anna Maria Coclitea*, Yujun Shib, Karen K. Gleasonc 
aInstitute of Solid State Physics, Graz University of Technology, Graz, Austria 
b Department of Chemistry, University of Calgary, Alberta, Canada 
cDepartment of Chemical Engineering, Massachusetts Institute of Thechnology, Boston, USA   
Abstract 
Preferred crystallographic orientation (texture) in thin films frequently has a strong effect on the properties of the 
materials and it is important for stable surface properties. Organized molecular films of poly-perfluorodecylacrylate 
p(PFDA) were deposited by initiated Chemical Vapor Deposition (iCVD). The high tendency of p(PFDA) to crystallize 
has been fully retained in the polymers prepared by iCVD. The degree of crystallinity and the preferred orientation of the 
perfluoro side chains, either parallel or perpendicular to the surface, were controlled by tuning the CVD process 
parameters (i.e. initiator to monomer flow rate ratio, filament temperature, and substrate temperature). Super-
hydrophobicity (advancing water contact angle, WCA, of 160°, low hysteresis of 5°), and oleophobicity (advancing CA 
with mineral oil of 120°) were achieved. Low hysteresis was associated with high crystallinity, particularly when the 
orientation of the crystallites resulted in the perfluoro side groups being oriented parallel to the surface. The latter texture 
resulted in smoother film (RMS roughness < 30 nm) than the texture with the chains oriented perpendicularly to the 
surface. This can be very advantageous for applications that require smooth but still crystalline films. 
 
© 2012 The Authors. Published by Elsevier Ltd.  
Selection and/or peer-review under responsibility of the Organizing Committee of EUROCVD 19. 
Keywords: iCVD, perfluoroacrylate coatings, PFDA, super-hydrophobicity. 
1. Introduction 
Interest continues into seeking a simple method for preparing artificial surfaces that exhibit both hydro- and 
oleo-phobic properties to resist fingerprints and avoid food stains on textiles. Low-surface-energy surfaces 
 
 
* Corresponding author. Tel.: +43 316 873 8970; fax: +43 316 873 108970. 
E-mail address: anna.coclite@tugraz.at 
Available online at www.sciencedirect.com
© 2013 The Authors. Published by Elsevier B.V.
Selection and peer-review under responsibility of Organizing Committee of EUROCVD 19.
 Anna Maria Coclite et al. /  Physics Procedia  46 ( 2013 )  56 – 61 57
have a wide range of applicability, as biocompatible surfaces (Ozaydin-Ince, Coclite, & Gleason, 2012), 
antifouling coatings (Yang, Asatekin, & Gleason, 2012), and low dielectric constant material for 
microelectronics (Lau, Murthy, Lewis, Caulfield, & Gleason, 2003).  
Super-hydrophobicity (WCA > 150° and hysteresis -i.e. difference between advancing and receding WCA- 
below 10°) is highly sought but often fluorocarbon coatings exhibit undesirably high WCA hysteresis (>30°) 
(Mao & Gleason, 2006). Many reasons can cause high hysteresis: surface reorientation and chain mobility, 
morphology that trap the water drops, chemical composition heterogeneities, presence of differing amounts of 
trapped low molecular weight polymeric species, etc (Cassie & Baxter, 1944; Wenzel, 1936).  
Fluorocarbon polymers have been demonstrated to have super-hydrophobic properties when some –CF3 
groups are exposed to the surface and when the polymeric chains have low mobility (A. M. Coclite, Y. J. Shi, 
& K. K. Gleason, 2012b; Lau, Bico, et al., 2003). 
Fluorocarbon coatings are difficult to process into this film form because of the insolubility of these 
polymers in most of the commonly used solvents. 
The possibility of depositing fluoropolymers by CVD is very attractive because there is no need of solvents 
or surfactant, which are difficult to find, expensive and persistent in the environment. Furthermore CVD 
allows depositing the fluorocarbon coating directly on microchannels, devices, hydrogels and this widens and 
simplify the applicability of this type of material. Among the CVD techniques, iCVD allows to obtain pure 
polymers with high structural retention, using low energy input and at high deposition rate. In iCVD the 
reactor is fed with an initiator, typically a peroxide, containing a labile bond. The thermal decomposition of 
the initiator occurs when a filament array, suspended few centimetres above the substrate, is heated. For 
peroxides, typical decomposition temperatures are below 300°C, which are too low to decompose also the 
monomer. Once the initiator is decomposed, its radicals react with the vinyl bonds of the monomer adsorbed 
on the substrate, kept at temperatures below 60°C. The polymerization propagates on the surface by adding 
more monomer molecules to the growing chains with radical ends. The polymerization terminates when the 
radical ends of the growing chains are capped by reaction with other radicals. 
In particular, perfluoroacrylates offer fast polymerization due to the unsaturated acrylate group and 
hydrophobicity for the fluorinated pendant chain. As a result of the –CF3 terminated side groups and comb-
like structure, the typical range of surface energies for fluorinated acrylic polymers is very low (5.6 to 7.8 
mN/m) (Gupta & Gleason, 2006).  
In this contribution we would like to outline the major results concerning the correlation between CVD 
deposition conditions and crystalline organization, with its effects on wettability. One innovative aspect will 
be also the investigation of the adhesion of the coating on the substrate. 
 
Nomenclature 
iCVD initiated Chemical Vapor Deposition 
PFDA perfluorodecylacrylate  
p(PFDA) poly- perfluorodecylacrylate 
TBPO     tert-butyl peroxide 
WCA     water contact angle 
58   Anna Maria Coclite et al. /  Physics Procedia  46 ( 2013 )  56 – 61 
2. Experimental details 
The deposition chamber was described in details in our previous work (A. M. Coclite et al., 2012b). The 
liquid monomer (1H,1H,2H,2H-perfluorodecyl acrylate, PFDA, 97% Aldrich) and initiator (tert-Butyl 
Peroxide, TBPO, 98% Aldrich) were used without further purification. p(PFDA) samples were deposited on a 
tricholorovinylsilane-pretreated and an untreated silicon wafer. The deposition conditions were as follows: 
monomer flow rate of 0.6 sccm, pressure of 200 mTorr, substrate temperatures of 40°C. The initiator flow rate 
was changed from 0.3 to 3.6 sccm, following the initiator over monomer flow rate ratio (I/M) reported in 
Table 1. The filament temperature was varied from 240 to 300°C. Each film was deposited up to a thickness 
of 200 ± 10 nm, monitored real-time by reflecting a He-Ne laser (JDS Uniphase) off the substrate/thin film 
and recording the interference laser signal intensity as a function of time. 
The film thicknesses were measured by ex-situ variable angle spectroscopy ellipsometry (VASE, JA 
Woollam M-2000). The crystalline state of the p-PFDA thin films was determined by X-ray diffraction 
(XRD). Contact angles (CA) were measured using a goniometer equipped with an automated dispenser 
(Model 500, Rame-Hart). The CA was measured using as liquid distilled water, mineral oil (Sigma Aldrich, 
CAS Number: 8042-47-5), n-heptane (99% Aldrich), n-octane (99% Aldrich) and n-decane (1000 μg mL-1 
Aldrich).  
Surface film morphology was investigated by Atomic Force Microscopy (AFM – Digital Instruments, 
D3100-1) and by Scanning Electron Microscopy (SEM, Hitachi, TM 3000) with an acceleration voltage of 15 
kV. The elemental analysis was done using angle-resolved X-ray photoelectron spectroscopy (ARXPS). 
Adhesion to silicon wafer was tested by following the stan- dard procedure reported in ASTM International 
tape test D3359-02. For this test, adhesive tape (3 M Scotch tape #600 as recommended in ASTM procedure) 
was applied on the sample surface and rapidly removed. The percentage of delamination was determined by 
dividing the tested surface into equally spaced grids and then manually counting the number of grids, which 
showed delamination. 
3. Results and Discussions 
The iCVD poly-(1 H ,1 H ,2 H ,2 H -perfluorodecylacrylate), p(PFDA) has been widely studied either pure 
(Gupta & Gleason, 2009; Haller, Frank-Finney, & Gupta, 2011) and copolymerized with other monomers 
(Baxamusa & Gleason, 2009; Coclite, Lund, Di Mundo, & Palumbo, 2013; Lau & Gleason, 2007). The side 
chains with eight perfluorinated carbons were completely retained during the polymerization giving 
interesting properties to the iCVD polymer such as hydrophobicity, oleophobicity, and crystallinity. 
The fluorinated chains of the p(PFDA) pending from the polymer backbone have a natural tendency to 
reorient toward themselves and form a crystalline bilayer structure, called smectic B phase. Semicrystalline 
polymers give stable surface properties, without hydrophobic recovery and create generally rough surfaces 
(root mean square roughness higher than 30 nm), which can be useful for enhancing cell growth or enhancing 
the hydrophobicity of the surface.  
The object of this study is showing that by tuning the iCVD parameters (initiator over monomer flow rate 
ratio and filament temperature), it is possible to tune also the degree of crystallinity in the film and the 
orientation of the crystallites (perpendicular or parallel to the surface) (A. M. Coclite et al., 2012b). Grafting 
the polymeric p(PFDA) chains to the surface has been investigated to enhance the crystallinity and wettability 
of the surfaces (A. M. Coclite, Y. Shi, & K. K. Gleason, 2012a).  
X-ray diffraction (XRD) analysis of the iCVD p(PFDA) showed the same crystal structure observed in 
conventionally synthesized p(PFDA), characterized by three main peaks assignable to successive diffraction 
 Anna Maria Coclite et al. /  Physics Procedia  46 ( 2013 )  56 – 61 59
orders of the bilayer structure: 32.4 Å (the length of the double layer), 16.2 Å (the length of a single chain) 
and 6.4 Å, characteristic of the hexagonal packing of the fluorochains. The crystallinity index (CI), calculated 
as the ratio of the areas of the crystalline peaks to the total area under the scattering curve, is reported in Table 
1. Changing the initiator over monomer flow rate ratio (I/M), resulted in different crystalline organization. At 
high I/M, the diffraction peaks were broad (low CI), while at low I/M sharp peaks have been observed (high 
CI). The differences in crystalline aggregation influenced the deposition rate, the wettability and the 
morphology. When the crystallinity index was its maximum the WCA hysteresis was minimal, while the 
contrary applied to the samples characterized by a low CI. The films with low CI were smoother than the film 
with high CI. 
 
I/M Tfil 
(°C) 
Grafting CI WCA 
hysteresis 
RMS 
roughness 
(nm) 
Mineral oil 
contact 
angle (°) 
Delamination 
(%) 
0.5 0.64 15 28 / 40 
2 0.65 18 34 / 8 
4 0.75 9 21 / 15 
6 
250 
0.15 30 10 / 18 
240 0.75 (90°) 5 24 / 15 
270 0.2 30 28 / 90 2 
300 
no 
0.5  40 57 / 20 
no 0.3 34 12 51 60 
3 290 yes 0.65 5 60 108 0 
Table 1. The table shows as the CVD conditions (initiator over monomer flow rate ratio, I/M and filament temperature, Tfil) influenced 
the film properties (crystallinity index, CI, water contact angle, WCA hysteresis, RMS roughness, mineral oil contact angle and % of 
delaminated film after tape testing). The CI was calculated considering the diffraction pattern measured when the x-ray beam was 
oriented at 0° with respect to the normal of the sample surface. Only in the case of the coating deposited at Tfil = 240°C for the CI was 
calculated for the diffraction pattern measured at 90°. 
 
At high filament temperature, 300 °C, sharp diffraction peaks were observable when the x-ray beam was 
oriented perpendicularly to the substrate while they were absent when x-ray beam was parallel to the 
substrate. This indicates a preferential vertical alignment of the perfluoro side-chains, which is called fiber-
like structure. At low filament temperature, 240 °C, instead, the diffraction peaks were sharp at 90° and broad 
at 0° indicating a change to a horizontal alignment. The different orientations have been schematized in Fig.1. 
60   Anna Maria Coclite et al. /  Physics Procedia  46 ( 2013 )  56 – 61 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 1. Schematics of the different chains orientation with respect to the substrate surface. Changing the iCVD conditions it is possible 
to obtain one texture or the other. The blue balls represent the carbon atoms, the oxygen atoms are in red and the fluorine atoms in gray. 
 
The difference in orientation was attributed to the different TBPO fragments created at temperature below 
and above 270°C, as it can be seen in Fig. 2. At low filament temperature the bulky tert-butoxy radical cannot 
penetrate a vertically oriented structure, therefore the chains orient parallel to the substrate. At high filament 
temperature, instead, the initiation is dominated by small methyl radicals, which allow a vertical orientation of 
the polymer chains. 
CH3
C
CH3
CH3 O
C
CH3
CH3CH3
O CH3
C
CH3
CH3 O
dĨŝů фϮϳϬΣ dĨŝů хϮϳϬΣϮ
CH3
C
CH3
O CH3Ϯ нϮ
 
 
Fig 2: TBPO Thermal decomposition paths. 
 
 
The polymers with the horizontally aligned chains showed lower RMS roughness and lower WCA hysteresis 
than the cases in which the chains were vertically aligned.  
As can be seen from Table 1 all the films deposited on bare Si substrate (i.e. without any grafting) showed 
delaminations after the tape test to different extent, independently from the crystalline organization. Therefore 
further investigations were conducted on grafted polymer chains. The use of trichlorovinyl silane as coupling 
agent resulted in covalent bonding between the substrate and the polymer. The grafted film showed enhanced 
crystalline fiber-like structures with high roughness. The grafted samples were superhydrophobic with 
advancing water contact angle of 160°, and hysteresis of only 5°. The grafted samples were also oleophobic as 
demonstrated by wetting the surface with different hydrocarbon oils drops. The grafted polymer exhibits 
oleophobicity contrarily to the ungrafted one, which shows much lower CAs. The grafted sample didn’t show 
any delamination after tape test, showing improved adhesion force to the substrate. 
 Anna Maria Coclite et al. /  Physics Procedia  46 ( 2013 )  56 – 61 61
Conclusions 
 
iCVD allows to deposit polymers that are identical to the counterpart deposited by conventional solution-
based methods. The possibility of retaining completely the functional groups has important consequences on 
the polymer properties. The long fluorinated chain of p(PFDA) is totally retained, resulting in crystalline 
aggregation. The orientation of the crystallites can be controlled by tuning the iCVD deposition conditions. 
The fine tuning and control of the deposition conditions, allowed also to obtain superhydrophobic and 
oleophobic surfaces which are very important for technological applications.  
Acknowledgements 
       The authors acknowledge financial support of the MIT Institute for Soldier Nanotechnologies (ISN) 
under Contract DAAD-19-02D-0002 with the U.S. Army Research Office. 
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with Protein Adsorption. Advanced Functional Materials, 19(21), 3489-3496. 
Cassie, A. B. D., & Baxter, S. (1944). Wettability of porous surfaces. Transasctions of Faraday Society, 40, 546-551.  
Coclite A.M., Lund, P., Di Mundo, R., & Palumbo, F. (2013). Novel hybrid fluoro-carboxylated copolymers deposited by initiated 
chemical vapor deposition as protonic membranes. Polymer, 54(1), 24-30.  
Coclite, A. M., Shi, Y.J., & Gleason, K. K. (2012a). Grafted crystalline poly-perfluoroacrylate structures for superhydrophobic and 
oleophobic functional coatings. Advanced Materials, 24(33), 4534-4539. 
Coclite, A. M., Shi, Y. J., & Gleason, K. K. (2012b). Controlling the Degree of Crystallinity and Preferred Crystallographic Orientation 
in Poly-Perfluorodecylacrylate Thin Films by Initiated Chemical Vapor Deposition. Advanced Functional Materials, 22(10), 2167-
2176.  
Gupta, M., & Gleason, K. K. (2006). Initiated chemical vapor deposition of poly(1H,1H,2H,2H-perfluorodecyl acrylate) thin films. 
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Macromolecules, 44(8), 2653-2659.   
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Superhydrophobic carbon nanotube forests. Nano Letters, 3(12), 1701-1705. 
Lau, K. K. S., & Gleason, K. K. (2007). All-dry synthesis and coating of methacrylic acid copolymers for controlled release. 
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Super-Hydrophobic and Oloephobic Crystalline Coatings by Initiated Chemical Vapor Deposition

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Mueller, Rainer

POSTER PRESENTATION Open Access
Rec. ST6Gal-I variants to control enzymatic
activity in processes of in vitro glycoengineering
Alfred M Engel1*, Harald Sobek1, Michael Greif1, Sebastian Malik2, Marco Thomann2, Christine Jung2,
Dietmar Reusch2, Doris Ribitsch4, Sabine Zitzenbacher4, Christiane Luley4, Katharina Schmoelzer4, Tibor Czabany5,
Bernd Nidetzky4,5, Helmut Schwab4,6, Rainer Mueller3
From 23rd European Society for Animal Cell Technology (ESACT) Meeting: Better Cells for Better Health
Lille, France. 23-26 June 2013
Background
Glycosylation is an important posttranslational modifica-
tion of proteins influencing protein folding, stability and
regulation of the biological activity. The sialyl mojety
(sialic acid, 5-N-acetylneuramic acid) is usually exposed
at the terminal position of N-glycosylation and there-
fore, a major contributor to biological recognition and
ligand function, e.g. IgG featuring terminal sialic acids
were shown to induce less inflammatory response and
increased serum half-life.
The biosynthesis of sialyl conjugates is controlled by a
set of sugar-active enzymes including sialyltransferases
which are classified as ST3, ST6 and ST8 based on the
hydroxyl position of the glycosyl acceptor the Neu5Ac is
transferred to [1]. The ST6 family consists of 2 subfami-
lies, ST6Gal and ST6GalNAc. ST6Gal catalyzes the
transfer of Neu5Ac residues to the hydroxyl group in
C6 of a terminal galactose residue of type 2 disaccharide
(Galb1-4GlcNAc).
To our knowledge, the access to recombinant ST6Gal-
I for therapeutic applications is still limited due to low
expression and/or poor activity in various hosts (Pichia
pastoris, Spodoptera frugiperda and E. coli).
The present study describes the high-yield expression
of two variants of human beta-galactoside alpha-2,6 sia-
lyltransferase 1 (ST6Gal-I, EC 2.4.99.1; data base entry
P15907) by transient gene expression in HEK293 cells
with yields >100 mg/L featuring distinct mono- (G2
+1SA) as well as bi- (G2+2SA) sialylation activity.
Materials and methods
Two N-terminally truncated fragments of human
ST6Gal-I (delta89, residues 89-406, and delta108, resi-
dues 109-406) were designed for transient gene expres-
sion (TGE): Instead of the natural leader sequence and
N-terminal residues, both ST6Gal-I coding regions har-
bor the Erythropoietin (EPO) signal sequence in order
to ensure correct processing of the polypeptides by the
secretion machinery. Following cloning into pM1MT,
expression of the ST6Gal-I coding sequences is under
control of a hCMV promoter followed by an intron A.
Sialyltransferase assays: 1. Asialofetuin was used as
acceptor and CMP-9F-NANA as donor substrate. Enzy-
matic activity was determined by measuring the transfer
of 9F-NANA to asialofetuin. 2. Recombinant humanized
IgG1 and IgG4 monoclonal antibodies (mabs), charac-
terized as G2+0SA, as well as desialylated EPO were
used as targets in sialylation experiments (30 μg
enzyme/300 μg target protein). Both enzyme variants of
ST6Gal-I (delta89 and delta108) were used under identi-
cal reaction conditions and the sialylation status was
analyzed by mass spectrometry.
Results
In using the suspension-adapted human embryonic kid-
ney (HEK) 293-F cell line, a modified serum-free Free-
Style™ medium platform plus transfection by the 293-
Free™ reagent, we were able to install a TGE shaker
fermentation process with product yields of up to 200
mg/L culture supernatant. Both variants delta89 and
delta108 could be isolated to >98% purity by a simple
2-step purification protocol.
To our surprise, both variants show a distinct and dif-
ferent sialylation activity as shown by sialylation kinetics
of a IgG4 molecule (Figure 1).
* Correspondence: alfred.engel@roche.com
1Professional Diagnostics, Roche Diagnostics GmbH, 82372 Penzberg,
Germany
Full list of author information is available at the end of the article
Engel et al. BMC Proceedings 2013, 7(Suppl 6):P110
http://www.biomedcentral.com/1753-6561/7/S6/P110
© 2013 Engel et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://
creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Recently, the crystal structure of the delta89 variant
could be determined as first human ST6Gal-I by SIRAS
phasing using an iodide soak as derivative I [2]: An
elongated glycan from a crystallographic neighbour
binds to the active site, mimicking a substrate complex.
An analysis of substrate interactions and comparison to
other sialyltransferases allows modelling of a Michaelis
complex and conclusions on the catalytic mechanism.
Due to their high expression rates and easy purifica-
tion, both recombinant variants (delta89 and delta108)
of human ST6Gal-I are available in large quantities and
high purity. Both variants are active with high molecular
weight substrates like monoclonal antibodies. To our
surprise, they show different performance in sialylation
experiments using with bi-antennary glycans such as
mabs as well as tetra-antennary glycans (data not
shown) as substrate. Under identical reaction conditions,
bi-sialylated glycans are obtained in using variant
delta89, whereas delta108 yields mono-sialylated glycans.
Our findings on variant delta108 are in contradiction
to previous studies [3] claiming that the conserved
QVWxKDS sequence, residues 94-100 of human
ST6Gal-I, being essential for its catalytic activity.
To our knowledge, these human ST6Gal-I variants are
the first enzymes available in large quantities and cur-
rently, recombinant alpha-2,3 sialyltransferase 1 (ST3Gal-
I) and beta-1,4 galactosyltransferase 2 (B4Gal-T2) are
developed in order to strengthen this enzyme portfolio.
Together with the already available donor substrates
(activated sugars), a complete set of reagents will be soon
available for the commercial glycoengineering of proteins.
Authors’ details
1Professional Diagnostics, Roche Diagnostics GmbH, 82372 Penzberg,
Germany. 2Pharma Biotech Development, Roche Diagnostics GmbH, 82372
Penzberg, Germany. 3Applied Science, Roche Diagnostics GmbH, 82372
Penzberg, Germany. 4ACIB GmbH, 8010 Graz, Austria. 5Institute of
Biotechnology and Biochemical Engineering, Graz University of Technology,
8010 Graz, Austria. 6Institute of Molecular Biotechnology, Graz University of
Technology, 8010 Graz, Austria.
Published: 4 December 2013
References
1. Weijers CA, Franssen MC, Visser GM: Glycosyltransferase-catalyzed
synthesis of bioactive oligosaccharides. Biotechnol Adv 2008, 26:436-456.
2. Kuhn B, Benz J, Greif M, Engel AM, Sobek H, Rudolph MG: Crystal structure
of human 2,6 sialyltransferase reveals mode of binding of complex
glycans. Acta Crystallographica 2013, D69:1826-1838.
3. Donadio S, Dubois C, Fichant G, Roybon L, Guillemot JC, Breton C, Ronin C:
Recognition of cell surface acceptors by two human alpha-2,6-
sialyltransferases produced in CHO cells. Biochimie 2003, 85:311-321.
doi:10.1186/1753-6561-7-S6-P110
Cite this article as: Engel et al.: Rec. ST6Gal-I variants to control
enzymatic activity in processes of in vitro glycoengineering. BMC
Proceedings 2013 7(Suppl 6):P110.
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Figure 1 Left panel: Variant delta89 yields 88% G2+2SA sialylation. However, after prolonged incubation (24 hrs), the bi-sialylation is
reduced to a stable mono-sialylation product, presumably by a sialydase activity. Right panel: Variant delta108 yields 70% G2+1SA and 7% G2
+2SA sialylation.
Engel et al. BMC Proceedings 2013, 7(Suppl 6):P110
http://www.biomedcentral.com/1753-6561/7/S6/P110
Page 2 of 2


Rec. ST6Gal-I variants to control enzymatic activity in processes of in vitro glycoengineering

Schroettner, Joerg

Lassnig, Alexander

Simulation model for cost estimation of integrated care concepts of heart failure patients

Karpenko-Jereb, Larisa

Kelterer, Anne-Marie

Berezina, Ninel

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Conductometric and computational study of cationic polymer membranes in H+ and Na+ forms at various hydration levels

Graz University of Technology

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