etc., a group 

 evolutionary 



evolutionary 

 My student, 



starch gel is employed because recoveries from 

 starch gel are ridiculously low. Recently we have 

 been working with an acrylamide gel system 

 which is quite satisfactory. From the limited 

 data which we have obtained I would say that 

 there seems to be a reasonably good relation- 

 ship between what you see and the quantities 

 present in the original mixture. 



GROSS: Are the genes contiguous? 



MASSARO: We don't know. 



EPEL: Are the shad, herring, 

 of fishes that are in the same 

 family? 



MASSARO: Yes. 



J, WRIGHT: In terms of the 

 scale, I think there's no pattern. 

 Novak, did a survey of LDH in various tissues 

 in various species and among those, gar and 

 bowfin are supposedly the most primitive. We 

 get 5 bands for the gar and only two bands for 

 the bowfin in almost all tissues looked at. In 

 contrast, the perch and bass would be further 

 up on the scale, and these have low numbers 

 of bands and it varies considerably. 



GROSS: Are these stages samples of these 

 species? 



J. WRIGHT: Yes, and there are individual 

 differences within some of these species. 



ZIMMERMAN: I just wonder how you can 

 explain the two bands in some species. Is this 

 explained in terms of an A and a. B? Don't you 

 need a minimum of 5 bands? 



MASSARO: The structure of the isozymes 

 of those species possessing two or three bands 

 of LDH activity has not been worked out. It is 

 conceivable, but improbable, that the LDH 

 molecule of these species is a dimer; if so, 

 one would not expect to find 5 bands of activity. 

 Also, it does not necessarily follow that tetra- 

 meric molecules will produce five bands of 

 activity since certain combinations of mono- 

 mers may not be allowed. 



TS'O: Did you study the mammalian case? 

 Do you know whether these subunits have to 

 function co-operatively or can each individual 

 subunit function separately? 



MASSARO: We don't know, but we are in the 

 process of attacking this problem. 



EPEL: Relating to what forms exist in vivo, 

 perhaps, in breaking up the cells you're selec- 

 tively causing some compartmental exchange? 

 MASSARO: That is possible. 

 EPEL: If you take tissue which specifically 

 has LDH-5 and one which has LDH-1, mix the 

 two homogenates together and then do a zymo- 

 gram, do you just get 1 and 5 or do you get 

 intermediates? Do you have to salt-f reeze to get 

 hybridization? 



MASSARO: In our experience you have to 

 either salt them heavily and freeze them or 

 salt them tremendously with a very high con- 

 centration of salt and let them sit around for a 

 long time before you'll get any hybridization. 



J. WRIGHT: What is the relationship of 

 these movements on starch and acrylamide? 



MASSARO: At comparable pH's and gel 

 densities the movements are reasonably similar 

 with the exception of LDH-5 which runs toward 

 the cathode in starch gel under our conditions 

 and toward the anode in acrylamide. 



J. WRIGHT: How about the cathode area of 

 insertion, now? Do you get LDH-5 moving back- 

 ward in the area of insertion? 



MASSARO: In starch, yes. Although, under 

 our conditions, LDH-5 is negatively charged, 

 a strong electroendosmotic effect propels it 

 cathodally. In acrylamide you do not have an 

 electroendosmotic effect so it moves toward 

 the positive pole. 



FERGUS: In regard to hybridizing, have 

 any attempts been made to use some non-LDH 

 protein? 



MASSARO: Yes, we tried it with MDH and 

 IDH, but got no results. 



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