種々の水分含量に調整した6種のデンプンについて,広幅PMRによる測定を行い,脱離時と吸着時における水分含量とPMRの吸収スペクトルの関係についてべた.その結果,　1.PMRの吸収スペクトルは水分の増大により高くなり,かつ幅が狭くなる.　2.PMRでのスペクトルの半値幅と水分含量の関係,吸着時と脱離時でほとんど差がなく,水分8%程度まで急激に減少し,次にややおだやかになる.　3.また,この関係は指数関数的であって,半対数グラフで2つの直線で示され,この交点はタピオカ19.1,ジャガイモ17.3,トウモロコシ16.2,サツマイモ15.7,コムギ14.4,コメ13.7%であった.また水分0に外挿した値は,ジャガイモ45,タピオカ33で,他のサツマイモ,コムギ,トウモロコシ,コメの各デンプンは35ppmで,ジャガイモデンプンが最も高い値を示した.　4.PMRでのスペクトルの半値幅と相対湿度の関係は,相対湿度の増大により半値幅は減少するが,脱離時の方が小さく,ヒステリシスが示された.

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　本研究の目的は,種々のトウモロコシ胚乳変異株の初期発芽段階で澱粉粒を走査電子顕微鏡により観察し,相対的な分解パターソと澱粉分解酵素による分解性を比較しようとするものである.4種の近交系と1種の単交配雑種トウモロコシのae胚乳変異株,および1種の近交系と1種の単交配雑種の5つの胚乳変異株,ならびにそれらの正常株の成熟穀粒を用いた.　正常株トウモロコシを4,6,あるいは8日発芽させたものの切断胚乳では,澱粉粒が酵素攻撃をうけた跡がみられた.酵素攻撃の様相は,anvitroで正常株トウモロコシ澱粉粒にα-アミラーゼを作用させたときのものによく似ていた.すなわち,多数の小さい穴が澱粉粒の表面にみとめられ,穴は粒の中心に向って進み,さらに分解が進むと階段状あるいは層状の内部構造がみえるものもあった.しかし,α-アミラーゼ以外の酵素による攻撃の可能性を示唆するような攻撃の跡もみられた.Oh43,C103,W64AおよびOh43×C103のae胚乳変異株の発芽胚乳の澱粉粒の多くは,表面が酵素攻撃をうけていないようにみえた.これらの観察は,invitroでae澱粉粒にアミラーゼを作用させたときにみられたものとよく似ていた.一方,発芽中のB37ae胚乳の澱粉粒の酵素攻撃の跡は,発芽中のB37正常株のものとほぼ同じであった.発芽中のsu₂,su₂O₂,wx,wxc₂および0₂変異株の胚乳澱粉粒については,発芽中の正常株のものとよく似た酵素攻撃の跡がみられた.

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　多糖類(おもにジャガイモ・デンプン)を用いてl-メントールの包接を行ない,次のような結果をえた.　(1)乾燥多糖類をメントールのメタノール溶液に浸漬し,母液ごと乾燥することにより,メントールをもっとも効率よく包接することができた.メントールの溶媒として,メタノール以外のものでは包接は行われなかった.また,包接錯体からのメントール抽出にも,メタノールがもっとも適していた.　(2)デンプン中の水分およびメントールの溶媒であるメタノール中の水分によって,包接が妨害された.　(3)デンプンにメントール・メタノール溶液を加えると,メタノールとメントールの両方がデンプン粒中にとりこまれるが,このときとりこまれたメタノールが乾燥時に揮散するときに,遊離状態で残存していたメントールと入れかわり,さらに多くのメントールが包接されるようになるものと思われた.　(4)多糖類によるメントールの包接は,非晶質および結晶質両方の領域で起こるが,結晶ミセルに包接されるメソトールの方が多いように思われた.また,ヘリックス構造を持たないセルロースにもメントールが包接されることから,この包接はおもに多糖類の分子鎖間で行われるものと思われた.　(5)多糖類・メントール包接錯体は乾熱に対しては非常に安定であったが,湿気に弱く高湿度の空気中ではメントールが徐々に消失してしまった.

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The major amylolytic enzyme present in Meicelase, a commercial crude cellulase preparation from Trichoderma viride; was purified by consecutive column chromatography, and characterized as a glucoamylase [EC 3.2.1.3]. The specific activity was brought to 18 .3 units of soluble starch-saccharif ying activity/mg of enzyme protein, and the enzyme showed a single band on polyacrylamide gel disc electrophoresis. Some properties of the purified glucoamylase were investigated. The molecular weight of the enzyme was estimated to be about 75, 000 on the basis of SDS polyacrylamide gel electrophoresis. The optimum pH and the optimum temperature for the activity of the enzyme were pH 5.0-5.5 and 60°C, respectively. The enzyme was stable over the range pH 5.0-7.0 at 4°C and was completely inactivated by heating at 90°C for 10 min. Hg²⁺ completely inhibited the enzyme, but other metal ions tested had little effect on the activity at the concentration of ions used (1 mM) . The action of the enzyme on glycogen, amylopectin, soluble starch, short chain amylose (DP =17.3), maltose, isomaltose and panose was studied. Glucose was the sole hydrolysis product found in digests of these substrates. At the same substrate concentration (0.075%, w/v) and enzyme concentration, the relative initial rates of glucose production from amylopectin, soluble starch, short chain amylose and maltose were about in the proportions 8 : 8 : 8 : 1. The K_m and V_max values at 30°C and pH 5.0 were calculated for the enzyme acting on glycogen, amylopectin, amylose, soluble starch, short chain amylose and maltose. By using the authentic anomers of D-glucopyranose under conditions limiting mutarotation, it was found that the condensation reactions catalyzed by glucoamylase require a donor substrate of specific configuration. The purified enzyme, which hydrolyzes amylaceous substrates to β-D-glucopyranose, was found to catalyze the rapid synthesis of maltose and isomaltose specifically from β-D-glucopyranose. The configurational inversion accompanying the condensations indicates that the D-glucopyranosyl portion of β-D-glucopyranose is interchanged with hydrogen at the C₄ or C₆ carbinol site of a second D-glucose molecule (glucosyl transfer).

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We confirmed that starch granules of potato, Chinese yam (tubers of Dioscorea batatas Decne), banana (Musa cavendish L.), lily (bulbs of Lilium spp.), gingko (seeds of Ginko biloba L.), high-amylose maize, East Indian lotus (tubers of Nelumbo nucifera Gaertn), Japanese chestnut (seeds of Castanea crenata Sieb. et Zucc.), kuzu (Japanese arrowroot, Pueraria lobata Ohwi), sweet potato were respectively in decreasing order more resistant to the attack of pancreatin than were those of normal maize, wheat, rice, red maize (Maize morado), and taro (roots of Colocasia antiquorum Schott). Among endosperm mutants of maize (Zea mays L.), starch granules of amylose-extender mutant were much more resistant to the action of amylases than were those of the normal counterpart. Starch granules of sugary-Ji and sugary-2 mutants were digested much faster than those of the normal counterpart by amylases. Starch granules of waxy, shrunken-2 and brittle-2 mutants tended to be digested faster than those of the normal. When opaque-2 was combined with each one of the endosperm mutants, it was observed that the starch granules of the double mutants were digested by amylases to an extent very comparable to their respective nonopaque single-mutant counterpart. The differences among the endosperm mutants in susceptibility of starch granules to the action of amylases disappeared following gelatinization of starch granules with alkali. Observations under a scanning electron microscope (SEM) revealed that starch granules resistant to the action of amylase showed after the action of amylases shapes and surfaces similar to the intact granules. On the other hand, starch granules susceptible to amylase showed numerous pin holes on the surface layer and the pores penetrated into the inner layers of the granule during the attack with amylases. For some of the granules the inner portion which appeared to be terraced or step-shaped could be seen. This may be indicative of layered or stratified internal structures of the granules. The other characteristic observations by SEM were striated structures on the surfaces of starch granules attacked by amylase, for example those of banana, lotus and lily.

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As an award address, the following three different works which had been achieved by our group since 1959 were presented. I) Glucose isomerization in alkaline aqueous solution To enhance the sweetness of glucose, the LOBRY de BRUYN-ALBERDA van EKENSTEIN reaction was studied. After examing the factors which affected on ketose formation, sugar degradation and coloration, we found that the reaction conditions-higher temperature and shorter reaction time-gave better results in higher fructose formation up to 35%, and lower sugar degradation (only 2-3%), ⁴⁾ compared with the conventional results of lower temperature and longer reaction time. This was proved by continuous isomerization using a semi pilot plant .⁷⁾ II) Fine structure of starch molecule Waxy maize starch was extensively treated by porcine pancreatic α-amylase to prepare αlimit dextrin. Then the fundamental branching structures were determined by the combined action of several enzymes, such as pullulanase, glucoamylase, β-amylase and porcine pancreatic a-amylase. Sixty five percent of α-1, 6 bond existed in amylopectin were obtained in singly branched oligosaccharides and the rest of the branches (35%) were in multiply branched oligosaccharides. These facts indicated the heterogeneity of branching in amylopectin molecules.¹²⁾ By chemical and physical studies of the structure of NAGELI amylodextrin, we proposed parallel double helix in crystalline part of amylopectin.¹⁵⁾ III) Maltohexaose forming amylase Maltohexaose forming amylase was discovered unexpectedly²¹ and identified as a novel exoamylase, ²² after glucoamylase, β-amylase and Ps, stutzeri maltotetraose forming amylase . This enzyme was purified and characterized its enzyme chemical properties.²³ The enzyme produced about 35-40% of maltohexaose from starch by exo-attack. By being improved the stability and productivity, the enzyme will be used in large scale production of maltohexaose.

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