2
428
A. Kumar, Kamaluddin
(
19.01 %) and Cyclic (Gly)2 (20.83 %), while alanine
the origin of life. MOCMo are able to catalyze the for-
mation of peptides from glycine or alanine without
applying drying/wetting cycling. Even at 60 °C after
7 days formation of peptide bond was observed when
MOCMo were used as a catalyst. Outer sphere metal in the
MOCMo showed different catalytic activity. ZnOCMo and
CoOCMo afforded Cyclic (Gly) , (Gly) , (Gly) and (Gly)
4
afforded (Ala) (10.43 %) and Cyclic (Ala) (15.75 %). It
2
2
was also observed that at higher temperature, i.e. 120 °C,
yield was almost constant (Figs. 1c, 2c, 3c, 4c, 5c, 6c, 7c).
It has also been found that the % yield of oligoglycine on
MOCMo was higher compared with that of oligoalanine. The
difference in the % yield may be attributed due to high acti-
vation energy for the formation of alanine peptide bond
2
2
3
from glycine, while Cyclic (Ala) and (Ala) from alanine.
2
2
(
Lawless and Levi 1979). It has been mentioned earlier that
ZnOCMo and CoOCMo having higher surface area showed
high catalytic activity and afforded high yield. The results
reported here, therefore, encourage investigation for further
possibilities of MOCMo as a catalyst in the prebiotic
chemistry.
the stability constants of the transition metal complexes with
peptides are lower as compared with the amino acids
(
Greenstein and Winitz 1961). This mechanism reveals the
facts that increasing chain length of amino acid leads to the
decreased concentration of the oligomers (Tables 2 and 3).
The trend in catalytic activity of MOCMo for the oligomeri-
zation of glycine and alanine with the % yield was as follows:
Acknowledgments One of the authors (Anand Kumar) is grateful to
Ministry of Human Resource and Development (MHRD), New Delhi,
India for providing financial assistance. Authors are also thankful to
Dr. Tokeer Ahmad, Department of Chemistry, Jamia Millia Islamia,
New Delhi, for surface area analysis of the samples.
ZnOCMo [ CoOCMo [ NiOCMo [ MnOCMo
[
CuOCMo [ CdOCMo [ FeOCMo
The Tables 2 and 3 shows the % yield of oligomerization
forglycineandalanineasafunctionofmetalcationspresentin
the outer sphere of the MOCMo. It is observed that outer
spheremetal in the MOCMo changes the catalytic activity and
thuseffectsontheyieldofoligomerizationproductsofglycine
and alanine are different. The present results show that
octacyanomolybdate with zinc and cobalt as outer sphere
metal were most effective metals for the production of long-
chain oligomers of glycine and alanine in high yield while the
iron was the least effective.
References
Alam T, Kamaluddin (1999) Interaction of aminopyridine with metal
hexacyanoferrates(II). Bull Chem Soc Jpn 72:1697–1703
Alam T, Kamaluddin (2000) Interaction of 2-amino, 3-amino and
4-aminopyridines with nickel and cobalt ferrocyanides. Colloids
Surf A 162:89–97
Alam T, Taranuum H, Viladkar S, Kamaluddin (1999) Oxidation of
aniline and its derivatives by manganese ferrocyanide. Oxid
Commun 22(4):599–609
Alam T, Tarannum H, Kumar N, Kamaluddin (2000a) Interaction of
2
-amino, 3-amino and 4-aminopyridines with Chromium and
Among MOCMo, ZnOCMo (surface area, SA
Manganese ferrocyanides. J Colloid Interf Sci 224:133–139
Alam T, Tarannum H, Kumar RMNV, Kamaluddin (2000b) Adsorp-
tion and oxidation of aromatic amines by metal hexacyanofer-
rates(II). Talanta 51:1097–1105
Alam T, Tarannum H, Ali SR, Kamaluddin (2002) Adsorption and
oxidation of aniline and anisidine by chromium ferrocyanide.
J Colloid Interf Sci 245:251–256
2
89 m g ) showed maximum catalytic activity while
-1
1
2
-1
FeOCMo (SA 3.91 m g ) showed minimum catalytic
activity. This observation implies that the surface areas of
the MOCMo play a dominating parameter for the peptide
formation in the glycine and alanine.
In order to analyze the product formed on MOCMo with
an alternate technique, the ESI–MS data obtained were also
scrutinized. Figures 10 and 11 show an ESI–MS spectrum
of products obtained when each glycine and alanine were
heated at 90 °C for 35 days in the presence of ZnOCMo. In
the ESI–MS spectra of glycine, mass 76.1 corresponds to
Ali SR, Kamaluddin (2006) Interaction of aromatic amino acids with
metal hexacyanochromate(III) complexes: a possible role in
chemical evolution. Bull Chem Soc Jpn 79(10):1541–1546
Ali SR, Kamaluddin (2007) Interaction of ribonucleotides with
hexacyanocobaltate(III): A possible role in chemical evolution.
Orig Life Evol Biosph 37:225–234
Ali SR, Ahmad J, Kamaluddin (2004) Interaction of ribose nucleo-
tides with metal ferrocyanides and its relevance in chemical
evolution. Colloids Surf A 236:165–169
Arrhenius T, Arrhenius G, Paplawsky W (1994) Archean geochem-
istry of formaldehyde and cyanide and the oligomerization of
cyanohydrin. Orig Life Evol Biosph 24:1–17
Bernal JD (1951) The physical basis of life. Rourledge and Kegan
Paul, London
?
?
[
Gly ? H] , 115 for [Cyc Gly ? H] , 132.9 for [Gly ?
2 2
?
H] , 189.9 for [Gly ? H] , and 246.6 for [Gly ? H] .
?
?
3
4
The MS spectra of alanine mass 90.1 corresponds to
?
Ala ? H] , 115 for [Cyc Ala ? H] , and 160.9 for
?
[
[
2
?
Ala ? H] . The ESI–MS data provided similar results as
2
in the case of obtained by HPLC.
Bujdak J, Rode BM (1996) The effect of smectite composition on the
catalysis of peptide bond formation. J Mol Evol 43:326–333
Bujdak J, Rode BM (1997a) Glycine oligomerization on silica and
alumina. React Kinet Catal Lett 62(2):261–286
Bujdak J, Rode BM (1997b) Silica, alumina, and clay-catalyzed
alanine peptide bond formation. J Mol Evol 45:457–466
Bujdak J, Rode BM (1999a) The effect of clay structure on peptide
bond formation catalysis. J Mol Catal A 144:129–136
Conclusion
The present study shows the potential importance of
MOCMo as prebiotic catalyst in chemical evolution and in
1
23