These are recommendations of the IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN). They have been approved for publication by the Executive Committee of IUB, and for publication as provisional recommendations by the Interdivisional Committee on Nomenclature and Symbols of IUPAC. The members of JCBN are H. B. F. Dixon (Chairman), A. Cornish-Bowden (Secretary), C. Liébecq (representing the IUB Committee of Editors of Biochemical Journals), K. L. Loening, G. P. Moss, J. Reedijk, S. F. Velick, and J. F. G. Vliegenthart. Comments may be sent to any member of the commission, or to its secretary: A. Cornish-Bowden, Department of Biochemistry, University of Birmingham, P.O. Box 363, Birmingham, England, B15 2TT. JCBN thanks the following for comments on these recommendations: C.E. Ballou, E. Buddecke, E. A. Davidson, R. J. Doyle, D. Duksin, J.-M. Ghuysen, T. Hardingham, V. C. Hascall, D. Heinegård, F. W. Hemming, D. Horton, R.C. Hughes, W.B. Jakoby, R.W. Jeanloz, O. Kandler, T. Laurent, Y.C. Lee, U. Lindahl, B. Lindberg, H. Lis, F.G. Loontiens, J. Montreuil, H. Muir, A. Neuberger, E.F. Neufeld, T. Osawa, L. Rodén, H. Schachter, R. Schauer, K. Schmid, G.D. Shockman, J.E. Silbert, C.C. Sweeley and I. Yamashina, as well as members, associate members and former members of the Nomenclature Committee of IUB (NC-IUB), namely H. Bielka, C.R. Cantor, P. Karlson, N. Sharon, E.J. Van Lenten and E.C. Webb.