3. Reagents for Diabetes Research

3-a) Kv2.1 / Kv2.2 Channel Blocker / Enhancer of Glucose-Dependent Insulin Secretion

Guangxitoxin-1E [manufactured by Peptide Institute]

Peptides with selective channel blocking activity have been used to clarify the specific function of the channels. Now, guangxitoxin-1E (GxTX-1E), which was isolated from the venom of spider (Plesiophrictus guangxiensis sp. nov.), has been identifi ed as a unique blocker for the K+ channels1).
GxTX-1E blocks Kv2.1 and Kv2.2 (and to a lesser extent Kv4.3) selectively, with a half-maximal concentration of less than 1 nmol/L.
Furthermore, this peptide does not signifi cantly affect the other K+ channels, Ca2+ channels, nor Na+ channels. In mouse β-cells, GxTX-1E inhibits 90% of delayed-rectifi er K+ current (IDR) and, as for Kv2.1, shifts the voltage dependence of channel activation to more depolarized potentials, a characteristic of gating-modifi er peptide. So far, Kv2.1 voltage-dependent K+ channels are known to be involved in i) enhancement of glucose-dependent insulin secretion 2) and ii) regulation of the pancreatic β-cell Ca2+ response to glucose3).
All these effects are attractive characteristics in relation to an investigation into the etiology of type 2 diabetes. Therefore, GxTX-1E would be useful tool for the diabetic research.

Guangxitoxin-1E
[Guangxitoxin-1E]
(Tarantula, Plesiophrictus guangxiensis sp. nov.)
(Trifl uoroacetate Form; Disulfi de bonds: Undetermined)
Glu-Gly-Glu-Cys-Gly-Gly-Phe-Trp-Trp-Lys-Cys-Gly-Ser-Gly-Lys-Pro-Ala-Cys-Cys-Pro-Lys-Tyr-Val-Cys-Ser-Pro-Lys-Trp-Gly-Leu-Cys-Asn-Phe-Pro-Met-Pro
C178H248N44O45S7 = 3948.6

[References]
1) J. Herrington, Y.-P. Zhou, R.M. Bugianesi, P.M. Dulski, Y. Feng, V.A. Warren, M.M. Smith, M.G. Kohler, V.M. Garsky, M. Sanchez, M. Wagner, K. Raphaelli, P. Banerjee, C. Ahaghotu, D. Wunderler, B.T. Priest, J.T. Mehl, M.L. Garcia, O.B. McManus, G.J. Kaczorowski, and R.S. Slaughter, : "Blockers of the delayedrectifi er current in pancreatic β-cells enhance glucose-dependent insulin secretion", Diabetes, 55, 1034-42 (2006). (Original)
2) P.E. MacDonald, S. Sewing, J. Wang, J.W. Joseph, S.R. Smukler, G. Sakellaropoulos, J.Wang, M.C. Saleh, C.B. Chan, R.G. Tsushima, A. M. Salapatek, and M.B. Wheeler, : "Inhibition of Kv2.1 voltage-dependent K+ channels in pancreatic beta-cells enhances glucose-dependent insulin secretion", J. Biol. Chem., 277, 44938-45 (2002). (Pharmacol.; Role of Kv2.1 in Glucose-Dependent Insulin Secretion)
3) N.A. Tamarina, A. Kuznetsov, L.E. Fridlyand, and L.H. Philipson, : "Delayed-rectifi er (KV2.1) regulation of pancreatic beta-cell calcium responses to glucose: inhibitor specifi city and modeling", Am. J. Physiol. Endocrinol. Metab., 289, E578-85 (2005). (Pharmacol.; Role of Kv2.1 in Glucose-Dependent Ca2+ response)
4) J. Herrington : "Gating modifi er peptides as probes of pancreatic β-cell physiology", Toxicon, 49, 231-8 (2007). (Review)
Description Wako Cat. # (Pkg. Size) Note
Guangxitoxin-1E [4433-s] 334-44331 (0.1 mg) Keep at -20°C

[ ]: Peptide Institute Product No.

3-b) Sulfonylurea (SU) Antidiabetic Agents

Description Wako Cat. # (Pkg. Size) Note
Acetohexamide , 97.0+% (Titration) 018-18731 (10g)
016-18732 (25g)
Sulfonylurea (SU) Agents for treating Type 2 Diabetes- ATP sensitive K+ Channel Blocker
Glibenclamide , 98.0+% (Titration) 078-03881 (  5g)
076-03882 (25g)
Gliclazide , 98.0+% (Titration) 071-04731 (10g)
079-04732 (25g)
Tolazamide , 96.0+% (Titration) 202-15211 (  5g)
200-15212 (25g)
Tolbutamide , 99.0+% (Titration) 209-09172 (25g)

3-c) Biguanide Antidiabetic Agents

Description Wako Cat. # (Pkg. Size) Note
Buformine Hydrochlorid , 98.0+% (Titration) 028-10052 (25g) Biguanide, a therapeutic agent for treating Type 2 Diabetes
Metformin Hydrochloride , 98.0+% (Titration) 138-15481 (100g)
130-15485 (500g)
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Wako Product Update Bio-No.2 [ page. 18 ]