ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS May 12, 1952

Review of

Lester: B-galactosidase of Lactose-less mtants of Escherichia coli, K-12

setae nciny

Title: "Lactose-leas"is monstrous. Luctose~-nonfermenting or just lactose would be
much batter.

The figures and tables would not be objectionable, except flop economy. Figures 1 and
5 (which partly duplicate published work, and might almost as well be sumaarized by the
K,) should be combined, making an arbitrary adjustuent of V if necessary. Figures 2, 3,

and 4 must be preserved. The comparisons would be more effective if each figure repre-
sented a given buffer, and the pH effects of the different mutants plotted on one figtre.

Table 1 is misleading: the growth requirements are irrelevant to the Lac character. It
would be much better to put the content of the table in the text, explaining the origin,
pertinent characteristics, and genetic behavior of the strains somewhat nore sxplicitly.
Here a oughout th r ti to tis behavi hould be documented.
Table °, Spr super? uous A single sentenae wh} “cover At. * veor ano ° n
p.5 "revertants". "Phenotypic reversion" is clearly meant. Y-70 probably gives no
true reverse-mutations, however, but more cften suppressors like those cited
on p. 16 ERRMXMMMAESEAX. Is 1t definitely excluded that suppressor mitations

whose lactose activity is suboptimal might account for the residual activity
of W-457

p. 9 The question of phosphate requirement was disposed of long since (References 3
and 7).

pp. 10-11 The interaction of pH and cation responses is complex, and not adequately
treated here. (See Cohen-Bazirs & Monod 1951 CR AS 232: 1515 ). For detailed
comparison, the buffers should be either iso-cationic, or loaded with sufficient
Na to minimize any competitions. For the purpose of empirical compardspns here,
the procedure is quite adequate, however,

p. 17 Deere's permeability hypothesis is now discredited.

p. 16 Lactase threshold is only another way of atating the paradox,

References abd p. 41 should include Monod, Cohen—Sazire and Cohn 1951 Acta Biochim.
73 585-599.

On the whole thia ia an excellent plece of work and should be published without

serious revision. Its deficiencies are only those of inadequaéé transposition from
an expanded dissertation to an economical journal paper.

* Tablea IV-V-VI might be combined for mre effective ;
comarison, keeping only the specific activity and Sincerely,
cw ated yield for each fraction. I would be willing

to trust 3 .
st the author for the arithmetic Joshua Lederberg

Associate Professor of Genetics