Henriks ZENKEVICS

Professor Henriks ZENKEVICS Institute of Biology, University of Latvia Miera iela 3 Salaspils, LV 2169 Latvia Phone: +371 7944988, +371 7945434 Fax: +371 9 345412 E-mail: zenkevics@email.lubi.edu.lv

Born: July 4, 1937, Riga, Latvia

Interests:

• Biochemistry of Vertebrate Pituitary Protein-like Hormones and Related Substances
• Biochemistry and Structure-Functional Aspects of Protein and Peptide Bioregulators
• Structure-Functional Investigations of Fish Gonadotropin(s).

Sturgeon (Acipenser stellatus; A.güldenstädti) and salmon (Oncorhynchus gorbuscha, Salmo salar) gonadotropic hormone (GTH) , its dimeric structure and the functional role of individual subunits as the specific components of the dimeric molecule has been investigated since 1975. For the first time chromatographically purified sturgeon and salmon GTH was isolated and it was shown that the pituitary gland of the fishes produces molecular charge variants or isoforms of GTH with different properties. It was shown that the quaternary structure of fish GTH is an asymmetric heterodimer, built like a mammalian GTH-s, consisting of two chemically heterologic subunits which differ functionally and are mutually bound noncovalently.

Also, structure-functional significance of some side chain radicals and sugar moiety were investigated using selective chemical modifications of both dimeric GTH and individual subunits.

The chemical structure of carbohydrate chains of the fish GTH and its subunits has been investigated by means of HPLC. It was shown that the sugar moieties play an important role in both molecular conformation and biological function of the hormone, individual subunits and its isoforms.The content and structure-functional role of sialic acids were determined in the sturgeon GTH.

In summary, the basic aspects of molecular properties and biological function of the fish GTH were investigated. The data obtained turned out to be valuable for better understanding both the GTH molecular composition and specificity of the molecular mechanisms of gametogenesis in the fish.

Languages: Latvian, Russian, English.

Education:

• University of Latvia (Faculty of Biology), 1963
• Dr.biol. (Candidate of Science in former USSR, Ph.D. in Western countries), Institute of Chemistry of Natural Compounds, Moscow, Russia, 1972
• Dr.habil.biol. (Doctor of Science in former USSR), I.Sechenov Institute of Evolutionary Physiology and Biochemistry, Leningrad, Russia, 1987

Experience:

• Lecturer, Faculty of Chemistry, University of Latvia, 1963-1965
• Engineer, Central Research Laboratory of Chemical Plant in Olaine, Latvia, 1965-67
• Postgraduate, Institute of Chemistry for Natural Compounds, Moscow, Russia, 1968-1970
• Junior Researcher, Institute of Biology, Latvian Academy of Sciences, 1971-76
• Senior Researcher, Head of Laboratory of Biochemistry, Institute of Biology, 1976-
• Deputy Director for Science , Institute of Biology, 1980 -

Honours and Awards:

• Corresponding Member, Latvian Academy of Sciences, 1992
• Professor, Institute of Biology of the University of Latvia, 1992

Professional Activities and Memberships:

• Member, Latvian Council of Science, 1997-
• Chairman, Commission of   Promotion, Latvian Council of Science, 1997- 
• Member, State Commission for Scientific Qualification, 1999 -
• Member, Latvian Council of Science Expert Committee for Biological Sciences, 1997- 2000
• Member of Editorial Advisory Board for Proceedings of Latvian Academy of Sciences, 1997- 2000;
  Vice-Chairman, 2000 -

Recent/Representative Publications:

• Monograph: H.A. Zenkevich. Fish Gonadotropic Hormone. Isolation and properties , 1992 , Riga: Zinatne Press, 224 pp. (in Russian, Summary in English)
• H.A. Zenkevich, V.P. Slanke , A.R. Valdman. Functional role of C-terminal part of the Russian sturgeon gonadotropin subunits. - Doklady Akademii Nauk SSSR, 1991, vol. 319, pp.1485-1487 (in Russian)
• H.A.Zenkevich, N.P.Arbatsky, V.P. Slanke, A.O. Zheltova, V.A. Derevitskaya. The structure of the carbohydrate chains of dimeric molecule and individual subunits of the Russian sturgeon gonadotropin. - Bioorganicheskaya Khimiya, 1992, vol. 18, pp. 226-234 (in Russian)
• H.A.Zenkevich, V.P. Slanke, Z.M. Lace, A.R. Valdman. Role of sialic acids in the sturgeon gonadotropin polymorphism. - Transact. (Doklady)  Russian Acad. Sci., 1993, vol. 331, pp. 632-635 (in Russian)
• H.A. Zenkevich, N.P. Arbatsky, A.O. Zheltova, V.P. Slanke, Z.M. Lace.  Characterization of the hydrocarbon chains of the humpback salmon gonadotropin molecular forms isolated using Concanavalin-A sepharose. - Bioorganicheskaya Khimiya, 1994, vol. 20, N 6, pp. 686-690 (in Russian).
• H. Zenkevics . Fish gonadotropic hormone: Structural-functional investigation. - Proc. Latv. Acad. Sci., 1994, N 5/6, pp. 82-89.
• H. Zenkevics, V. Slanke, V. Vose. Isohormone-inhibitor of biological activity of Baltic salmon Salmo salar L.  gonadotropin. - Transact. (Doklady)  Russian Acad. Sci., 1996, vol. 347, pp. 818-820 (in Russian).
• H. Zenkevics, V. Vose, I. Vosekalne, A. Bucena. Functional role of sugar moiety of the  ß-subunit in sturgeon gonadotropin. - Transact. (Doklady)  Russian Acad. Sci., 1999, vol. 364, N 6, pp. 828-831 (in Russian).
• H. Zenkevics, V. Vose, I. Vosekalne, A. Bucena. Partial degycosylation of alpha subunit modifies sturgeon gonadotropin function. - Acta Biochim. Pol., 2000, vol.47, N 3, pp. 815-819.
• V. Vose, H. Zenkevics, A. Bucena. Copper ions influences sturgeon gonadropin function. -  Proc. Latv. Acad. Sci., B, 2000, vol. 54, N 1/2, pp.  46-47.
• H. Zenkevics, V. Vose,  A. Bucena. Molecular form of the sturgeon gonadotropin which does not adsorb on ConcanavalinA. - Transact. (Doklady)  Russian Acad. Sci., 2001, vol. 376, N 3, pp. 401- 403. 
• V.Vose, H.Zenkevics, A.Bucena. Cadmium reduces the hormonal sensivity of frog oocytes. -  Proc. Latv. Acad. Sci., B, 2002, vol. 56, N 1/2, pp.  61-64.
• H.Zenkevics. Fifty years of the Institute of Biology: retrospective view on the development and research  of the Institue. -  Proc. Latv. Acad. Sci., B, 2002, vol. 56, N 4/5, pp.  193-206.
• H. Zenkevics, V. Vose,  A. Bucena. Functional role of tryptophan residues in sturgeon gonadotropic hormone. -  Proc. Latv. Acad. Sci., B, 2003, vol. 57,  pp.  187-191.
• H.Zenkevics, V.Vose, I.Vosekalna,  A.Bucena. Structural-functional role of disulphide bonds in sturgeon gonadotropin. - Proc. Latv. Acad. Sci., B, 2004, vol. 58, N3/4, pp. 127-130.
• H.Zenkevics, M.Klavins, V.Vose, A.Bucena. Humic acid reduces gonadotropin activity and hormonal sensivity of frog oocytes. - Aquatic Toxicology, 2005, vol. 75, pp.380-383.
• H.Zenkevics, V.Vose, I.Vosekalna,  A.Bucena. Secondary structure of sturgeon gonadotropin ß subunit isoforms. - - Proc. Latv. Acad. Sci., B, 2006, vol. 60, N 2/3, pp. 77-80.
• H.Zenkevics, V.Vose, A.Butsena. The key role of guanidine groups in the hormonal function of gonadotropin of the Russian sturgeon. - - Doklady Biochemistry and Biophysics, 2006, vol. 410, pp. 278-289.

Research Projects:

• H.Zenkevics (Head of Project). Investigation of the Relationship between the Molecular Properties and Specific Function of Fish Gonadotropin. Latvian Council of Science (1991-1993).
• H.Zenkevics (Head of Project). Investigation of Molecular and Biological Properties of Protein-like Hormones from Fish Pituitary: Possible Relationship with Some Hydroecological Factors. Latvian Council of Science (1993-1996).
• H.Zenkevics (Head of Project). Investigation of Regularities in Fish Gonadotropic Hormone Molecular Properties and Biological Functions. Latvian Council of Science (1996-2000).
• H.Zenkevics (Head of Project). Investigation of  Fish Reproduction Regulator - Gonadotropic Hormone Molecular Forms and Analogues. Latvian Council of Science (2001 -2004).
• H.Zenkevics (Head of Project). Investigation of Fish Reproduction Regulator – Gonadotropic Hormone Molecular Forms and Analogues. Latvian Council of Science (2005 - ).

Last update 12.09.2007