Research on Methionine in Whale(On Methionine (CH3S-CH2-CH2-CHNH2) Content)

ICOOH

Masami Yoshida

I. Introduction
Methionine is an amino acid containing sulphur and was discoveredin the hydrolyzed product of casein by Mueller in the United Statesin 1922. This .was synthetically produced by Bagar and Coyne in 1928
and named it methionine. After this, a large number of people attempted
to synthesize and isolate it.
From the nutrition point of vlew, methionine, together with cystine, isan ,important amino acid as a source of sulphur for animals. According
to recent researches, it is said that methionine transforms into cystine ina living body. In 1937, Rose(I) reported that methionine is a necessity andcystine is not· a necessity and explained that it aids growth, and disproved
Osborne an Mendel's theory.·
Furthermore, in regard to its content, Baernstein in 1932, made determinations of methionine, a characteristic methylthiol group, of various proteins
and reported that methionine content is greater in animal protein than invegetable protein.
. 1.8%(2)2.3%(3)Glycinin
Lact albumin
2.0%(2)
4.5%(3)
Gliadin
Egg albumin
2.2%(3)3.1%(3)Zein
Casein
3.14%(4)Sardine flesh
3.66%(2)
Beef
Whale meat (Kind unknown) 2.92%(4) ·In regard to methionine content in whale meat, the only report is byTomiyama.
The auther made determinations of methionine content in whale meatin order to determine its nutritional value, compared with other foodstuff
and as a first step in effective separation and utilization of methionine
from whale meat; a relatively detailed analysis· of its content in various
parts of sei. whale, sperm whale and fin whale was made.
There are various ·methods for making this determination, but Baernstein's method was used here.
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Baernstein made quantitative analysis under the assumption thatmethoxyl and methylimid bases does not exist in protein molecules andthat ·the quantity of methyl iodide obtained by reaction with HI results
only from CH2S.
For accuracy, methionine content in beef protein and casein wasdetermined and compared with previous literatures.
II. Experiment,.
(a) Collection of Samples
Heart, tongue, ventral meat (Sunoko) and ·meat was obtained from a
13.6 meter male sei whale at Ayukawa, Miyagi Prefecture. The length and sex of the fin whale and sperm whale are not known, but both wereobtained at Ayukawa. For beef, the round of beef obtained on themarket was used.
(b) Preparation of samples
Whale and beef protein
Flesh is fitst sliced thinly and soaked in cold water, wh'ch is heatedto 36°C and changed to new water. The it is bo]ed once. This is thenexpressed and water removed as much as possible, I chopped in a meat
chopper, dried in sun, extracted with boiling alcohol for 4 hours andthen with ether for 10 hours and ·dried for 3 'hours at 105-110°C.
Balem
After washing with water, it is dried at room temperature, cut in thinslices, extracted with ether for 10 hours and dried for 3 hours at 105ll 00C.
(c) Outline of Operation
Sample is decomposed with HI and CHJ produced, absorbed in alcoholic AgNO:i solution to form AgI, filtered and the residual Ag determined
quantitatively with 2/100 N KCNS using m:cro-burette, The methionine
quantity is calculated from the difference. in Ag· quantity in a blank test.
The cond:tions for the determination were a.s follows ; In the originalreport, it is stated that about 90% of the CH:I come over in the 1 sthour but the remainder usually takes several hours more, and Baernstein
adopt about 15 hours, but here the reaction time is 6 hours, about 0.5 gof the sample is decomposed with 10 cc. of HI (s. g. 1.7) and absorbed
in 20 cc. of alcoholic AgNOs solution.

Masami Yoshida104

The apparatus is as follows :II

AgN03 Solution

20% CdS0.1 Alcoholic AgN03 Solution

H2S01(d) Experimental results
Table No. 1.
ContentSampleHeartTongue
Ventral meat (Sunoko)
Belly meat
Head meat
Back meat
Tail meat

Sei Whale

4.80
4.22
4.17
3.42
3.33
2.78
2.71
4.82

Fin Whale Meat
Sperm Whale MeatBlue Whale Bajeen
Fin Whale Baleen
Sei Whale Baleen

3.46
0.82
1.92
1.96

The methionine content of beef and casein was determined by thesame method and compared with previous literature, it "is as follow.s :Table No. 2.,
AnalystSampleCaseinBeef protein
Whale meat protein

Baernstein<2)

Baernstein(a)

3.53%
3.36
3.25

3.1%

Tomiyama,
HanadaC4)

Yoshida

2.54%

3.94%

2.92

3.06

3.663.56

In Table No. l, the average methionine content of 3.06% in the variousparts o_f s~i whale, which is ordinaray called meat is very close to. thevalue 2.92% by Tomiyama, · which was obtained by the difference between

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105

total S for Denis Benedicts method and cystine S fer Okuda's method.
However, there is something here which require special attention. In
the case of casein. several experiments' gave the result of 3.94±0.02%, but
in the case of beef and whale meat, there are some cases when the resultsof several experiments does not coincide. As to the cause of this discrepancy, on considering Table No. 1, it appears that there is a tendency forthe value to be h;gh in parts '\Vhich are rich in connective tissues. Thus
it was thought that there may b.e some relation between ·methionine content and the connective tissue contained in the sample, so the following
experiment was performed.
The kind of whale is not known but the sample was prepqred in thesame manner as before, connective tissue was separated as much as possible from the meat and methionine of each was determined. The result
is as in Table No. 3.
Table No. 3.
Connective Tissue

Meat Scrap

3.22%

1.43%

That is, from. the determination results, it is clear that methionine
content is greater in the conective tissues than in the meat scraps.
III. Summary(1) The methio.1ine content of the part ordinarily called meat is 3.06%
in sei whale, 4.82% in fin whale and 3.46% in sperm whale.
(2) Of the different parts of sei whale, content is largest in heart, next
in the portion rich in connective tissues (tongue, ventral) and then inthe part where there is little connect~ve tissues (meat).
(3) The difference in methionine content in the different part of whale
meat is thought due to the difference in the quantity of connective
tissues in the various parts.
(4) The large content in the heart is thought to be of great interest inrelation to physiological action of renewal.
Refferences
( 1)
( 2)
( 3)
( 4)

Womack Kemmerer: J. Biol Chem. 121 (1937) 403.
Baerstein: ]. Biol. Chem. 97 (1932) 663.
Baerstein: ]. Biol. Chem. 115 (1936) 25.
Tomiyama Ha~ada; Nogei Kogakukai Shi 10 (1934) 53.