IBC - 蔡蔭和

Research

I started to study the venom proteins of Taiwanese cobra and krait in 1977. I also studied the midgut chymotrypsin and trypsin and the hemolymph clottable protein and transglutaminase of Penaes shrimps. Later, we used Molecular Biology tools to study snake venom. Venomous snakes of medical or biological importance (e.g. habu, king cobra), monotypic (e.g. Azemiops, Deinagkistrodon), endemic to Taiwan (e.g. T. gracilis), or of high biodiversity usually attracted me. We have used FPLC, RP-HPLC, LC-MS/MS, and cDNA cloning/sequencing to study venom proteins; and analyzed the in vitro and in vivo functions. Transcriptomics, Proteomics, Glycomics and Bioinformatics have been included in our research in recent years. Our lab. has solved many toxin sequences and deposited in Genbank; and published about 80 papers on venom toxins before 2020.

Snake toxin-families have undergone rapid evolution and venom variations are associated with phylogeographic and environmental changes of the snakes during past 40~6 million years. We have explored and compared the geographic variations of the following venom species: (1) Habu P. mucrosquamatus from North and South Taiwan, and different species of Protobothrops; (2) Bamboo viper T. stejnegeri from seven regions over Taiwan; (3) Malayan pitviper C. rhodostoma from five S.E. Asian countries; (4) Rattlesnake C. v. viridis inhabiting different States of USA, from Montana to New Mexico; (5) Russell’s vipers (D. russellii and D. siamensis); Daboia venom from Myanmar and eastern India are similar to each other, while those from Pakistan, Indonesia islands, Sri Lanka, Thailand, china and Taiwan show clear differences; (6) King cobra from four Asian countries and China; (7) E. India B. fasciatus. We cloned/sequenced the cDNAs encoding ten venom PLA₂ paralogs and four 3Finger-toxins and confirmed that the PLA₂sequences completely match the previous Edman-degradation results by T.B. Low’s lab. of our institute (possibly used Thailand B. fasciatus venom), only the 3Finger-toxins show great geographic variations. (8) Temple viper T. wagleri of two Malayan/Asian regions. Significant geographic variations in viperid and king-cobra venom phospholipases A₂ have been demonstrated and the findings may help the snakebite treatment and antivenin formulation.

We also succeeded in the recombinant expression and site-directed mutagenesis of a habu phospholipase-neurotoxin, and performed “knock-out” study of each of the N-glycosylation site in acutobin (the thrombin like enzyme from Deinagkistrodon). Both projects are expensive and long-term, but the results are not much appreciated. We have also collaborated with Prof. Khoo K.H. on a genus-wide comparison of the glycan-profiles of representative viperid venoms; MS/MS and glycopeptide analysis revealed unique disialylated multiantennary N-glycans on acutobin. There have been some exciting “first time” findings in my lab., including: (A) Cheng A.C. showed that a Kunitz-type protease inhibitor from Russell’s viper is a heparin-dependent inhibitor of “activated protein C”; (B) Chen H.S. discovered a thrombin-binding snaclect and clarified its anticoagulant mechanism; (C) Tsai S.H. showed that K49-PLA₂ of T. stejnegeri binds LPS very strongly, and serve as an antibacterial agents; (D) Collaborating with Yang Z.M. (Xanxii Normal Univ., China) we discovered that crotoxin-like neurotoxic PLA₂dimers are present in G. intermedius venom.

Degrees and Positions Held

1979 – 1980 Postdoctoral Res. fellow, Dept. Biochemistry, U. of Chicago
1976 – 1977 Postdoctoral Res. , Thiman Labs., UC, Santa Cruz, USA
1971 – 1976 Ph.D., Dept. Chemistry , Northwestern University, USA
1967 – 1971 B.S., Agricultural Chemistry , National Taiwan University

1988 – 2014 Research Fellow, Inst. Biological Chemistry, Academia Sinica, Taiwan
1988 – 2014 Professor, Inst. Biochemical Sciences, National Taiwan University, Taiwan
1999 – 2002 Director , Inst. Biochemical Sciences, National Taiwan University, Taiwan
1996 – 1996 Visiting Professor, Dept. of Chem. Engine., Johns Hopkins Univ., USA
1993 – 1995 Deputy Director , Institute of Biological Chemistry, Academia Sinica, Taiwan
1988 – 1988 Visiting scholar, Dept. Struct. & Cell. Biol., Univ. Texas, San Antonio, USA
1977 – 1988 Associate Research Fellow, Institute of Biological Chemistry, Academia Sinica, Taiwan