Toxkon, 1973, Vol. 13, pp . 311-312 . Peraamon Prea . Printed in Great Britain.

LETTER TO THE EDITOR A RESPONSE TO "NOMENCLATURE OF NATURALLY OCCURRING PEPTIDES" (Acceptedjor publication 22 April 197

Sut : Before a system ofnomenclature (classification) can be devised, we think that the basic objectives of such a system should be agreed upon. To us, a system which classifies the various polypeptides in snake venoms (and other venomous secretions) should ideally be based upon the following : The (i) genus and species of organism from which it is isolated . (ü) The chemical properties (i.e. amino acid sequence) . (iii) The immunochemical properties. (iv) The function (i.e. pharmacological properties). We then want to use these properties to give us as simple a classification (nomenclature) as possible . This classification should not cause any confusion with, e.g. the enzyme classification system, and should be relatively easy to apply. The system we proposed, was set up to follow the ideal case outlined above. To restate how it works, the following scheme can be given for naming a venom polypeptide ("toxin"). Roman Gemts species V Alphabet Numeral `Genus species' identifies the organism from which it was isolated . This can be any Genus and species. `V' signifies `venom component'. `Roman' is replaced by a roman numeral which gives the immunochemical class of the polypeptide. For `Alphabet' any symbol which a committee agrees upon, can be used to signify the chemical properties and function (pharmacological properties) of the polypeptide . The `Numeral' is then used to discriminate between isopolypeptides. This system seems to us to conform to the requirements set out above for a classification system . The major drawbacks seen by Banks and Shipolini in this classification, relate to (i) "the difficulty of determining the precise pharmacological properties" and (ü) "the limited scope of the system". As to point (i) we can just state that in the proposed system no `Alphabet' classification can be made before the chemical and/or functional (pharmacological) properties have been determined . This is a fact any classification system has to contend with. In most cases the chemical structure (i.e. sequence) will give a facile assignment, but known pharmacological properties will be of use. We think here of, e.g. `short neurotoxins' of Naja haje venom which have been found with very homologous sequences to other short neurotoxins, but with greatly diminished toxicity . In such a case they probably cannot be called short neurotoxins, and we will have to await their functional (pharmacological) characterization before they can be classified (by any system). TOXICON 1975 Yo7. I3

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This reasoning, when applied to the problems these two authors state, shows that one will have to determine what, e.g. bee venom 2.8.1 is, before classifying it. With 4.0.1 of bee venom you will just have to choose an all-inclusive name, or if this is not possible, simply decide which is the major effect and use that as the basis for assigning a name. The system we proposed, clearly can accommodate bee venom components, albeit under different classes than those found in snake venoms . If no immunological properties are known, or if such a polypeptide is very weakly antigenic, no `Roman' letter is added as superscript. As far as their comments concerning the Dendroaspis viridis polypeptides are concerned, we feel (as stated in our original letter) that minutiae like unusual amino acids (-SH groups) one amino acid deletions, etc., should not lead to different classifications. Therefore, we do not see why every difference in pharmacological effect (such as species differences in response to polypeptides) should be used to multiply the number of classes of compound . We are, e.g. open to a suggestion that the long and short neurotoxins be classified as one class, since it can be argued that the small difference in chemical structure is not very important. The misclassification of the fraction 5 of Naja ntelanoleuca venom was caused by not adhering to the principle that you should know what you have, before classifying it. The proposed system definitely does not exclude, e.g. vipers, crotalids, insects, etc. The case of bee venom has been mentioned, and, e.g. under this system we could already classify the protease inhibitor of Russell's viper venom as Yipera palesriraae V, 2. The crotoxin complex can also find a nook in the proposed system when their properties are known, and the same holds true for the amphibian skin polypeptides although the small size of the latter suggests using their systematic names as nomenclature. In conclusion we want to state that our proposal was made as such and that we think that an International Committee is the proper organ to work out and set up a proper nomenclature system. It seems that this should be done soon, or we will have the same large problems in `toxin' nomenclature as existed in enzyme nomenclature a number of years ago. National Chtmical Research Laboratory, South African Council for Scientific and Industrial Research, P.O . Box 395, Pretoria, South ~%rica.

TOXICON 1973 YoG 13

D . P. BOTES, F. H . H . Caeissox, F. J. JovsExT, A .1 . Louw, A . J. C. STxYnoM, D. J. $TRYDOM and C. C . Vrt,loErr

Letter: A response to "nomenclature of naturally occurring peptides".

Toxkon, 1973, Vol. 13, pp . 311-312 . Peraamon Prea . Printed in Great Britain. LETTER TO THE EDITOR A RESPONSE TO "NOMENCLATURE OF NATURALLY OCCURRI...
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