Thanks to all who replied to my question. Virgil -- Virgil Schirf Department of Biochemistry, Rm 535C The University of Texas Health Science Center at San Antonio 7703 Floyd Curl Dr. San Antonio TX 78229 email: schirfv at biochem.uthscsa.edu Voicemail: (210) 567-6590 FAX: (210)567-6595 http://cauma.uthscsa.edu